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Records |
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Author |
Kirschhock, C.E.A.; Liang, D.; Van Tendeloo, G.; Fécant, A.; Hastoye, G.; Vanbutsele, G.; Bats, N.; Guillon, E.; Martens, J.A. |
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Title |
Ordered end-member of ZSM-48 zeolite family |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
21 |
Issue |
2 |
Pages |
371-380 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
ZSM-48 and related zeolites are considered to be highly disordered structures. Different polytypes can be clearly distinguished by simulation of high-resolution electron microscopy images. Synthesis of phase-pure polytypes was attempted. One of the investigated samples crystallized via seeding designated as COK-8 consisted of nanoscopic, needlelike crystals with a very large length/width ratio, growing along the pore direction. These specimens are phase-pure polytype 6 (PT6, numbering according to Lobo and van Koningsveld). Aggregates of these nanoneedles occasionally contained a second polytype: PT1. The latter polytype occurred more abundantly in larger crystal rods in an IZM-1 sample crystallized in ethylene glycol. Here too, the isolated crystallites mainly consist of large, defect-free regions of PT6. A simulation of polytype lattice energies offers a rational explanation for the observed polytypical intergrowth formation. |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000262605200026 |
Publication Date |
2008-12-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
30 |
Open Access |
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Notes |
Fwo; Goa |
Approved |
Most recent IF: 9.466; 2009 IF: 5.368 |
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Call Number |
UA @ lucian @ c:irua:76032 |
Serial |
2503 |
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Permanent link to this record |
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Author |
Armelao, L.; Bertagnolli, H.; Bleiner, D.; Groenewolt, M.; Gross, S.; Krishnan, V.; Sada, C.; Schubert, U.; Tondello, E.; Zattin, A. |
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Title |
Highly dispersed mixed zirconia and hafnia nanoparticles in a silica matrix: First example of a ZrO2-HfO2-SiO2 ternary oxide system |
Type |
A1 Journal article |
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Year |
2007 |
Publication |
Advanced functional materials |
Abbreviated Journal |
Adv Funct Mater |
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Volume |
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Issue |
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Pages |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
ZrO2 and HfO2 nanoparticles are homogeneously dispersed in SiO2 matrices (supported film and bulk powders) by copolymerization of two oxozirconium and oxohafnium clusters (M4O(2)(OMc)(12), M= Zr, Hf; OMc = OC(O)-C(CH3)=CH2) with (methacryloxypropyl)trimethoxysilane (MAPTMS, (CH2=C(CH3)C(O)O)-(CH2)(3)Si(OCH3)(3)). After calcination (at a temperature >= 800 degrees C), a silica matrix with homogeneously distributed MO2 nanocrystallites is obtained. This route yields a spatially homogeneous dispersion of the metal precursors inside the silica matrix, which is maintained during calcination. The composition of the films and the powders is studied before and after calcination by using Fourier transform infrared (FTIR) analysis, X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). The local environment of the metal atoms in one of the calcined samples is investigated by using X-ray Absorption Fine Structure (XAFS) spectroscopy. Through X-ray diffraction (XRD) the crystallization of Hf and Zr oxides is seen at temperatures higher than those expected for the pure oxides, and transmission electron microscopy (TEM) shows the presence of well-distributed and isolated crystalline oxide nanoparticles (540 nm). |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000248062100011 |
Publication Date |
2007-05-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1616-301x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
34 |
Open Access |
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Notes |
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Approved |
Most recent IF: 12.124; 2007 IF: 7.496 |
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Call Number |
UA @ lucian @ c:irua:95083 |
Serial |
4521 |
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Permanent link to this record |
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Author |
Berends, A.C.; van der Stam, W.; Hofmann, J.P.; Bladt, E.; Meeldijk, J.D.; Bals, S.; de Donega, C.M. |
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Title |
Interplay between surface chemistry, precursor reactivity, and temperature determines outcome of ZnS shelling reactions on CuInS2 nanocrystals |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
30 |
Issue |
30 |
Pages |
2400-2413 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
ZnS shelling of I-III-VI(2 )nanocrystals (NCs) invariably leads to blue-shifts in both the absorption and photoluminescence spectra. These observations imply that the outcome of ZnS shelling reactions on I-III-VI2 colloidal NCs results from a complex interplay between several processes taking place in solution, at the surface of, and within the seed NC. However, a fundamental understanding of the factors determining the balance between these different processes is still lacking. In this work, we address this need by investigating the impact of precursor reactivity, reaction temperature, and surface chemistry (due to the washing procedure) on the outcome of ZnS shelling reactions on CuInS2 NCs using a seeded growth approach. We demonstrate that low reaction temperatures (150 degrees C) favor etching, cation exchange, and alloying regardless of the precursors used. Heteroepitaxial shell overgrowth becomes the dominant process only if reactive S- and Zn-precursors (S-ODE/OLAM and ZnI2 ) and high reaction temperatures (210 degrees C) are used, although a certain degree of heterointerfacial alloying still occurs. Remarkably, the presence of residual acetate at the surface of CIS seed NCs washed with ethanol is shown to facilitate heteroepitaxial shell overgrowth, yielding for the first time CIS/ZnS core/shell NCs displaying red-shifted absorption spectra, in agreement with the spectral shifts expected for a type-I band alignment. The insights provided by this work pave the way toward the design of improved synthesis strategies to CIS/ZnS core/shell and alloy NCs with tailored elemental distribution profiles, allowing precise tuning of the optoelectronic properties of the resulting materials. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
American Chemical Society |
Place of Publication |
Washington, D.C |
Editor |
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Language |
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Wos |
000430023700027 |
Publication Date |
2018-03-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
85 |
Open Access |
OpenAccess |
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Notes |
; Annelies van der Bok is gratefully acknowledged for performing the ICP measurements. A.C.B. and C.d.M.D. acknowledge financial support from the division of Chemical Sciences (CW) of The Netherlands Organization for Scientific Research (NWO) under Grant No. ECHO.712.014.001. S.B. and E.B. acknowledge financial support from European Research Council (ERC Starting Grant No. 335078-COLOURATOMS). ; Ecas_Sara |
Approved |
Most recent IF: 9.466 |
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Call Number |
UA @ lucian @ c:irua:150772UA @ admin @ c:irua:150772 |
Serial |
4972 |
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Permanent link to this record |
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Author |
Li, D.Y.; Zeng, Y.J.; Batuk, D.; Pereira, L.M.C.; Ye, Z.Z.; Fleischmann, C.; Menghini, M.; Nikitenko, S.; Hadermann, J.; Temst, K.; Vantomme, A.; Van Bael, M.J.; Locquet, J.P.; Van Haesendonck, C.; |
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Title |
Relaxor ferroelectricity and magnetoelectric coupling in ZnOCo nanocomposite thin films : beyond multiferroic composites |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
Acs Appl Mater Inter |
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Volume |
6 |
Issue |
7 |
Pages |
4737-4742 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
ZnOCo nanocomposite thin films are synthesized by combination of pulsed laser deposition of ZnO and Co ion implantation. Both superparamagnetism and relaxor ferroelectricity as well as magnetoelectric coupling in the nanocomposites have been demonstrated. The unexpected relaxor ferroelectricity is believed to be the result of the local lattice distortion induced by the incorporation of the Co nanoparticles. Magnetoelectric coupling can be attributed to the interaction between the electric dipole moments and the magnetic moments, which are both induced by the incorporation of Co. The introduced ZnOCo nanocomposite thin films are different from conventional strain-mediated multiferroic composites. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000334572800018 |
Publication Date |
2014-03-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1944-8244;1944-8252; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.504 |
Times cited |
21 |
Open Access |
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Notes |
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Approved |
Most recent IF: 7.504; 2014 IF: 6.723 |
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Call Number |
UA @ lucian @ c:irua:117063 |
Serial |
2864 |
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Permanent link to this record |
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Author |
Ghica, C.; Enculescu, I.; Nistor, L.C.; Matei, E.; Van Tendeloo, G. |
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Title |
Electrochemical growth and characterization of nanostructured ZnO thin films |
Type |
A1 Journal article |
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Year |
2008 |
Publication |
Journal of optoelectronics and advanced materials |
Abbreviated Journal |
J Optoelectron Adv M |
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Volume |
10 |
Issue |
12 |
Pages |
3237-3240 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
ZnO is a wide band-gap (ca. 3.4 eV) semiconductor, piezoelectric, pyroelectric, biocompatible, transparent in the visible spectrum and UV light emitting material. The fabrication in 2001 of the first nanobelts of semiconductor oxide materials lead to a rapid expansion of researches concerning one dimensional nanostructures (nanotubes, nanowires, nanobelts), given their possible application in optics, optoelectronics, piezoelectricity, catalysis. Researches carried on up to date evidenced the possibility to obtain an extraordinary variety of ZnO nanostructures, in function of the experimental parameters and the used growth methods. In this work we present morphostructural results on nanostructured ZnO layers obtained by electrochemical deposition. The films have been grown on gold covered glass plates and Si wafers, in various experimental conditions such as: nature of the wetting agents, electrical polarization of the substrate (continuous, pulsed). The influence of the growth conditions on the crystalline structure and morphology of the films is revealed by scanning and transmission electron microscopy studies. The films show a variety of growth morphologies, from entangled-wires-like to honeycomb-like layers. These large-specific-surface layers will be tested as nanostructured substrates for photovoltaic cells with improved efficiency. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Bucharest |
Editor |
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Language |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1454-4164 |
ISBN |
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Additional Links |
UA library record; WoS full record; |
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Impact Factor |
0.449 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 0.449; 2008 IF: 0.577 |
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Call Number |
UA @ lucian @ c:irua:75746 |
Serial |
899 |
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Permanent link to this record |
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Author |
Dixit, H.; Tandon, N.; Cottenier, S.; Saniz, R.; Lamoen, D.; Partoens, B. |
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Title |
First-principles study of possible shallow donors in ZnAl2O4 spinel |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
87 |
Issue |
17 |
Pages |
174101-174107 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
ZnAl2O4 (gahnite) is a ceramic which is considered a possible transparent conducting oxide (TCO) due to its wide band gap and transparency for UV. Defects play an important role in controlling the conductivity of a TCO material along with the dopant, which is the main source of conductivity in an otherwise insulating oxide. A comprehensive first-principles density functional theory study for point defects in ZnAl2O4 spinel is presented using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) to overcome the band gap problem. We have investigated the formation energies of intrinsic defects which include the Zn, Al, and O vacancy and the antisite defects: Zn at the Al site (ZnAl) and Al at the Zn site (AlZn). The antisite defect AlZn has the lowest formation energy and acts as a shallow donor, indicating possible n-type conductivity in ZnAl2O4 spinel by Al doping. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000318653300001 |
Publication Date |
2013-05-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
50 |
Open Access |
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Notes |
Iwt; Fwo |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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Call Number |
UA @ lucian @ c:irua:108769 |
Serial |
1219 |
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Permanent link to this record |
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Author |
Afanasov, I.M.; Van Tendeloo, G. |
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Title |
Zirconia-modified exfoliated graphite |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Inorganic materials |
Abbreviated Journal |
Inorg Mater+ |
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Volume |
47 |
Issue |
6 |
Pages |
603-608 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Zirconia has been incorporated into exfoliated graphite (EG) through the anodic polarization in the natural graphite-ZrO(NO3)2-HNO3-H2O system, followed by flash heating. The thermal properties of the oxidized graphites employed as precursors to EG have been studied by thermogravimetry in combination with differential scanning calorimetry, and the distribution of ZrO2 particles in the EG has been assessed by scanning and transmission electron microscopy. Conditions are described for the preparation of EG with bulk densities in the range 1.34.7 g/l and ZrO2 contents in the range 434 wt %. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000291698100008 |
Publication Date |
2011-05-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0020-1685;1608-3172; |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
0.62 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 0.62; 2011 IF: 0.414 |
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Call Number |
UA @ lucian @ c:irua:90447 |
Serial |
3933 |
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Permanent link to this record |
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Author |
Nicholls, D.; Li, R.R.; Ware, B.; Pansegrau, C.; Çakir, D.; Hoffmann, M.R.; Oncel, N. |
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Title |
Scanning tunneling microscopy and density functional theory study on zinc(II)-phthalocyanine tetrasulfonic acid on bilayer epitaxial graphene on silicon carbide(0001) |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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Volume |
119 |
Issue |
119 |
Pages |
9845-9850 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
Zinc(II)-phthalocyanine tetrasulfonic acid (Zn-PcS) molecules physisorbed on bilayer epitaxial graphene on silicon carbide (SiC(0001)) were studied by using scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT). Two different methods were used to deposit Zn-PcS molecules and regardless of the method being used, the surface coverage stayed very low indicating the weakness of surface-molecule interaction. STS measurements revealed that derivative of tunneling current with respect to voltage (dI/dV) measured on Zn-PcS molecules did not exhibit the characteristic dip observed on dI/dV curves of pristine bilayer epitaxial graphene. DFT calculations show that the energy of the lowest unoccupied molecular orbital (LUMO) of the Zn-PcS molecule is below the Dirac point of graphene which enhances local density of states (LDOS). We attribute the disappearance of the dip in the dI/dV curves measured on the Zn-PcS/bilayer system to the LUMO of Zn-PcS. Charge density calculations along Zn-PcS/graphene interface reveal that there is a small charge transfer from graphene to the molecule. Calculated adsorption energy (3.13 eV) of the molecule is notably low and is consistent with the observed low surface coverage at room temperature. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000354339000020 |
Publication Date |
2015-04-15 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447;1932-7455; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
3 |
Open Access |
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Notes |
; We gratefully acknowledge the NSF (Grant Nos.: DMR-1306101, EPS-814442, and EPS-1354366) for financial support. ; |
Approved |
Most recent IF: 4.536; 2015 IF: 4.772 |
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Call Number |
c:irua:126370 |
Serial |
2947 |
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Permanent link to this record |
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Author |
Kirkwood, N.; De Backer, A.; Altantzis, T.; Winckelmans, N.; Longo, A.; Antolinez, F.V.; Rabouw, F.T.; De Trizio, L.; Geuchies, J.J.; Mulder, J.T.; Renaud, N.; Bals, S.; Manna, L.; Houtepen, A.J. |
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Title |
Locating and controlling the Zn content in In(Zn)P quantum dots |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
32 |
Issue |
32 |
Pages |
557-565 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Zinc is routinely employed in the synthesis of InP quantum dots (QDs) to improve the photoluminescence efficiency and carrier mobility of the resulting In(Zn)P alloy nanostructures. The exact location of Zn in the final structures and the mechanism by which it enhances the optoelectronic properties of the QDs is debated. We use synchrotron X-ray absorbance spectroscopy to show that the majority of Zn in In(Zn)P QDs is located at their surface as Zn-carboxylates. However, a small amount of Zn is present inside the bulk of the QDs with the consequent contraction of their lattice, as confirmed by combining high resolution high-angle annular dark-field imaging scanning transmission electron microscopy (HAADF-STEM) with statistical parameter estimation theory. We further demonstrate that the Zn content and its incorporation into the QDs can be tuned by the ligation of commonly employed Zn carboxylate precursors: the use of highly reactive Zn-acetate leads to the formation of undesired Zn3P2 and the final nanostructures being characterized by broad optical features, whereas Zn-carboxylates with longer carbon chains lead to InP crystals with much lower zinc content and narrow optical features. These results can explain the differences between structural and optical properties of In(Zn)P samples reported across the literature, and provide a rational method to tune the amount of Zn in InP nanocrystals and to drive the incorporation of Zn either as surface Zn-carboxylate, as a substitutional dopant inside the InP crystal lattice, or even predominantly as Zn3P2. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000507721600056 |
Publication Date |
2019-12-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
39 |
Open Access |
OpenAccess |
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Notes |
A.J.H. acknowledges support from the European Research Council Horizon 2020 ERC Grant Agreement No. 678004 (Doping on Demand). This research is supported by the Dutch Technology Foundation TTW, which is part of The Netherlands Organization for Scientific Research (NWO), and which is partly funded by Ministry of Economic Affairs. SB acknowledges funding from the European Research Council (grant 815128 REALNANO). The authors gratefully acknowledge funding from the Research Foundation Flanders (FWO, Belgium) through project funding G.0381.16N and a postdoctoral grant to A.D.B. AJH, LM and JM acknowledge support from the H2020 Collaborative Project TEQ (Grant No. 766900).; sygma |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:165234 |
Serial |
5438 |
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Permanent link to this record |
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Author |
Hernández-Nieves, A.D.; Partoens, B.; Peeters, F.M. |
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Title |
Electronic and magnetic properties of superlattices of graphene/graphane nanoribbons with different edge hydrogenation |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
82 |
Issue |
16 |
Pages |
165412-165412,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Zigzag graphene nanoribbons patterned on graphane are studied using spin-polarized ab initio calculations. We found that the electronic and magnetic properties of the graphene/graphane superlattice strongly depends on the degree of hydrogenation at the interfaces between the two materials. When both zigzag interfaces are fully hydrogenated, the superlattice behaves like a freestanding zigzag graphene nanoribbon, and the magnetic ground state is antiferromagnetic. When one of the interfaces is half hydrogenated, the magnetic ground state becomes ferromagnetic, and the system is very close to being a half metal with possible spintronics applications whereas the magnetic ground state of the superlattice with both interfaces half hydrogenated is again antiferromagnetic. In this last case, both edges of the graphane nanoribbon also contribute to the total magnetization of the system. All the spin-polarized ground states are semiconducting, independent of the degree of hydrogenation of the interfaces. The ab initio results are supplemented by a simple tight-binding analysis that captures the main qualitative features. Our ab initio results show that patterned hydrogenation of graphene is a promising way to obtain stable graphene nanoribbons with interesting technological applications. |
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Language |
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Wos |
000282569500011 |
Publication Date |
2010-10-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.836 |
Times cited |
46 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI), the Belgian Science Policy (IAP), and the collaborative project FWO-MINCyT (FW/08/01). A. D. H. acknowledges also support from ANPCyT (under Grant No. PICT2008-2236) ; |
Approved |
Most recent IF: 3.836; 2010 IF: 3.774 |
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Call Number |
UA @ lucian @ c:irua:85030 |
Serial |
996 |
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Permanent link to this record |
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Author |
Mulder, J.T.; Meijer, M.S.; van Blaaderen, J.J.; du Fosse, I.; Jenkinson, K.; Bals, S.; Manna, L.; Houtepen, A.J. |
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Title |
Understanding and preventing photoluminescence quenching to achieve unity photoluminescence quantum yield in Yb:YLF nanocrystals |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
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Volume |
15 |
Issue |
2 |
Pages |
3274-3286 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Ytterbium-doped LiYF4 (Yb:YLF) is a commonly used material for laser applications, as a photon upconversion medium, and for optical refrigeration. As nanocrystals (NCs), the material is also of interest for biological and physical applications. Unfortunately, as with most phosphors, with the reduction in size comes a large reduction of the photoluminescence quantum yield (PLQY), which is typically associated with an increase in surface-related PL quenching. Here, we report the synthesis of bipyramidal Yb:YLF NCs with a short axis of similar to 60 nm. We systematically study and remove all sources of PL quenching in these NCs. By chemically removing all traces of water from the reaction mixture, we obtain NCs that exhibit a near-unity PLQY for an Yb3+ concentration below 20%. At higher Yb3+ concentrations, efficient concentration quenching occurs. The surface PL quenching is mitigated by growing an undoped YLF shell around the NC core, resulting in near-unity PLQY values even for fully Yb3+-based LiYbF4 cores. This unambiguously shows that the only remaining quenching sites in core-only Yb:YLF NCs reside on the surface and that concentration quenching is due to energy transfer to the surface. Monte Carlo simulations can reproduce the concentration dependence of the PLQY. Surprisingly, Fo''rster resonance energy transfer does not give satisfactory agreement with the experimental data, whereas nearest-neighbor energy transfer does. This work demonstrates that Yb3+-based nanophosphors can be synthesized with a quality close to that of bulk single crystals. The high Yb3+ concentration in the LiYbF4/LiYF4 core/shell nanocrystals increases the weak Yb3+ absorption, making these materials highly promising for fundamental studies and increasing their effectiveness in bioapplications and optical refrigeration. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000912997300001 |
Publication Date |
2023-01-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1944-8244 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.5 |
Times cited |
3 |
Open Access |
OpenAccess |
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Notes |
This project has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 766900 (Testing the Large-Scale Limit of Quantum Mechanics). A.J.H. and I.d.F. further acknowledge the European Research Council Horizon 2020 ERC Grant Agreement No. 678004 (Doping on Demand) for financial support. The authors thank Freddy Rabouw and Andries Meijerink (Utrecht University) for very fruitful discussions and extremely useful advice. The author s thank Jos Thieme for his help with the laser setups used . The authors furthermore thank Niranjan Saikumar for proofreading the manuscript. |
Approved |
Most recent IF: 9.5; 2023 IF: 7.504 |
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Call Number |
UA @ admin @ c:irua:194317 |
Serial |
7348 |
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Permanent link to this record |
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Author |
Berdiyorov, G.R.; Chao, X.H.; Peeters, F.M.; Wang, H.B.; Moshchalkov, V.V.; Zhu, B.Y. |
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Title |
Magnetoresistance oscillations in superconducting strips : a Ginzburg-Landau study |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
22 |
Pages |
224504-224508 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within the time-dependent Ginzburg-Landau theory we study the dynamic properties of current-carrying superconducting strips in the presence of a perpendicular magnetic field. We found pronounced voltage peaks as a function of the magnetic field, the amplitude of which depends both on sample dimensions and external parameters. These voltage oscillations are a consequence of moving vortices, which undergo alternating static and dynamic phases. At higher fields or for high currents, the continuous motion of vortices is responsible for the monotonic background on which the resistance oscillations due to the entry of additional vortices are superimposed. Mechanisms for such vortex-assisted resistance oscillations are discussed. Qualitative changes in the magnetoresistance curves are observed in the presence of random defects, which affect the dynamics of vortices in the system. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000312064300004 |
Publication Date |
2012-12-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
31 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the ESF-NES program. G. R. B. acknowledges support from FWO-Vl. B.Y.Z. acknowledges the support from the MOST 973 Projects No. 2011CBA00110 and No. 2009CB930803, and the National Natural Science Foundation of China. V. V. M. acknowledges support from the Methusalem Funding by the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:105969 |
Serial |
1930 |
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Permanent link to this record |
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Author |
Lipavsky, P.; Elmurodov, A.; Lin, P.-J.; Matlock, P.; Berdiyorov, G.R. |
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Title |
Effect of normal current corrections on the vortex dynamics in type-II superconductors |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
14 |
Pages |
144516-144518 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within the time-dependent Ginzburg-Landau theory we discuss the effect of nonmagnetic interactions between the normal current and supercurrent in the presence of electric and magnetic fields. The correction due to the current-current interactions is shown to have a transient character so that it contributes only when a system evolves. Numerical studies for thin current-carrying superconducting strips with no magnetic feedback show that the effect of the normal current corrections is more pronounced in the resistive state where fast-moving kinematic vortices are formed. Simulations also reveal that the largest contribution due to current-current interactions appears near the sample edges, where the vortices reach their maximal velocity. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000309809700007 |
Publication Date |
2012-10-15 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
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|
Notes |
; The authors are grateful to Alex Gurevich and Tom Lemberger who brought the longitudinal f-sum rule to our attention. This work was supported by Grants GACR P204/10/0687 and P204/11/0015. We also acknowledge the support from the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). G.R.B. acknowledges individual support from FWO-Vl. P.-J.L. acknowledges support from Old Dominion University. P.M. acknowledges support through UA research index SR-614-1203. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:102168 |
Serial |
827 |
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Permanent link to this record |
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Author |
Liu, C.-Y.; Berdiyorov, G.R.; Milošević, M.V. |
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Title |
Vortex states in layered mesoscopic superconductors |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
83 |
Issue |
10 |
Pages |
104524-104524,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within the Ginzburg-Landau theory, we study the vortex structures in three-dimensional anisotropic mesoscopic superconductors in the presence of a uniform magnetic field. Anisotropy is included through varied Tc in different layers of the sample and leads to distinct differences in the vortex states and their free energy. Several unconventional states are found, some comprising vortex clusters or exhibiting asymmetry. In a tilted magnetic field, we found second-order transitions between different vortex states, although vortex entry is generally a first-order transition in mesoscopic samples. In multilayered samples the kinked vortex strings are formed owing to the competing interactions of vortices with Meissner currents and the weak-link boundaries. The length and deformation of vortex fragments are determined solely by the inclination and strength of applied magnetic field, and this lock-in does not depend on the degree of anisotropy between the superconducting layers. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000288998200003 |
Publication Date |
2011-03-31 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
22 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:89375 |
Serial |
3888 |
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Permanent link to this record |
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Author |
Baelus, B.J.; Peeters, F.M. |
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Title |
The effect of surface defects on the vortex expulsion and penetration in mesoscopic superconducting disks |
Type |
A1 Journal article |
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Year |
2004 |
Publication |
Physica: C : superconductivity
T2 – 7th International Conference on Materials and Mechanisms of, Superconductive and High Temperature Superconductors, MAY 25-30, 2003, Rio de Janeiro, BRAZIL |
Abbreviated Journal |
Physica C |
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Volume |
408 |
Issue |
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Pages |
543-544 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within the framework of the nonlinear Ginzburg-Landau theory we investigate how the vortex expulsion and penetration fields are influenced by the presence of surface defects in superconducting disks with zero thickness. We studied different types and sizes of defects. (C) 2004 Elsevier B.V. All rights reserved. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000224051700228 |
Publication Date |
2004-08-31 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0921-4534; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.404 |
Times cited |
1 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.404; 2004 IF: 1.072 |
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Call Number |
UA @ lucian @ c:irua:102759 |
Serial |
3576 |
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Permanent link to this record |
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Author |
da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
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Title |
Energy levels of bilayer graphene quantum dots |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
115437 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within a tight binding approach we investigate the energy levels of hexagonal and triangular bilayer graphene (BLG) quantum dots (QDs) with zigzag and armchair edges. We study AA- and AB-(Bernal) stacked BLG QDs and obtain the energy levels in both the absence and the presence of a perpendicular electric field (i.e., biased BLG QDs). Our results show that the size dependence of the energy levels is different from that of monolayer graphene QDs. The energy spectrum of AB-stacked BLG QDs with zigzag edges exhibits edge states which spread out into the opened energy gap in the presence of a perpendicular electric field. We found that the behavior of these edges states is different for the hexagonal and triangular geometries. In the case of AA-stacked BLG QDs, the electron and hole energy levels cross each other in both cases of armchair and zigzag edges as the dot size or the applied bias increases. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000361663700003 |
Publication Date |
2015-09-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
21 |
Open Access |
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Notes |
; This work was financially supported by CNPq, under contract NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation under the process number BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, and the Brazilian Program Science Without Borders (CsF). ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:128726 |
Serial |
4173 |
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Permanent link to this record |
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Author |
Zarenia, M.; Pereira, J.M.; Chaves, A.; Peeters, F.M.; Farias, G.A. |
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Title |
Simplified model for the energy levels of quantum rings in single layer and bilayer graphene |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
81 |
Issue |
4 |
Pages |
045431,1-045431,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within a minimal model, we present analytical expressions for the eigenstates and eigenvalues of carriers confined in quantum rings in monolayer and bilayer graphene. The calculations were performed in the context of the continuum model by solving the Dirac equation for a zero width ring geometry, i.e., by freezing out the carrier radial motion. We include the effect of an external magnetic field and show the appearance of Aharonov-Bohm oscillations and of a nonzero gap in the spectrum. Our minimal model gives insight on the energy spectrum of graphene-based quantum rings and models different aspects of finite width rings. |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000277186000010 |
Publication Date |
2010-01-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
76 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the Bilateral program between Flanders and Brazil, and the Brazilian Council for Research (CNPq). ; |
Approved |
Most recent IF: 3.836; 2010 IF: 3.774 |
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Call Number |
UA @ lucian @ c:irua:82866 |
Serial |
3005 |
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Permanent link to this record |
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Author |
Amini, M.N.; Leenaerts, O.; Partoens, B.; Lamoen, D. |
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Title |
Graphane- and fluorographene-based quantum dots |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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Volume |
117 |
Issue |
31 |
Pages |
16242-16247 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
With the help of first-principles calculations, we investigate graphane/fluorographene heterostructures with special attention for graphane and fluorographene-based quantum dots. Graphane and fluorographene have large electronic band gaps, and we show that their band structures exhibit a strong type-II alignment. In this way, it is possible to obtain confined electron states in fluorographene nanostructures by embedding them in a graphane crystal. Bound hole states can be created in graphane domains embedded in a fluorographene environment. For circular graphane/fluorographene quantum dots, localized states can be observed in the band gap if the size of the radii is larger than approximately 4 to 5 Å. |
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Corporate Author |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000323082300046 |
Publication Date |
2013-07-15 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447;1932-7455; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
14 |
Open Access |
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Notes |
FWO; GOW; Hercules |
Approved |
Most recent IF: 4.536; 2013 IF: 4.835 |
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Call Number |
UA @ lucian @ c:irua:109457 |
Serial |
1367 |
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Permanent link to this record |
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Author |
Khelifi, S.; Brammertz, G.; Choubrac, L.; Batuk, M.; Yang, S.; Meuris, M.; Barreau, N.; Hadermann, J.; Vrielinck, H.; Poelman, D.; Neyts, K.; Vermang, B.; Lauwaert, J. |
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Title |
The path towards efficient wide band gap thin-film kesterite solar cells with transparent back contact for viable tandem application |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Solar Energy Materials And Solar Cells |
Abbreviated Journal |
Sol Energ Mat Sol C |
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Volume |
219 |
Issue |
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Pages |
110824 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Wide band gap thin-film kesterite solar cell based on non-toxic and earth-abundant materials might be a suitable candidate as a top cell for tandem configuration in combination with crystalline silicon as a bottom solar cell. For this purpose and based on parameters we have extracted from electrical and optical characterization techniques of Cu2ZnGeSe4 absorbers and solar cells, a model has been developed to describe the kesterite top cell efficiency limitations and to investigate the different possible configurations with transparent back contact for fourterminal tandem solar cell application. Furthermore, we have studied the tandem solar cell performance in view of the band gap and the transparency of the kesterite top cell and back contact engineering. Our detailed analysis shows that a kesterite top cell with efficiency > 14%, a band gap in the range of 1.5-1.7 eV and transparency above 80% at the sub-band gaps photons energies are required to achieve a tandem cell with higher efficiency than with a single silicon solar cell. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000591683500002 |
Publication Date |
2020-10-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0927-0248 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.784 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
The authors would like to acknowledge the SWInG project financed by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 640868 and the Research Foundation Flanders-Hercules Foundation (FWO-Vlaanderen, project No AUGE/13/16:FT-IMAGER). |
Approved |
Most recent IF: 4.784 |
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Call Number |
EMAT @ emat @c:irua:174337 |
Serial |
6706 |
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Permanent link to this record |
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Author |
Liu, F.; Meng, J.; Xia, F.; Liu, Z.; Peng, H.; Sun, C.; Xu, L.; Van Tendeloo, G.; Mai, L.; Wu, J. |
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Title |
Origin of the extra capacity in nitrogen-doped porous carbon nanofibers for high-performance potassium ion batteries |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal Of Materials Chemistry A |
Abbreviated Journal |
J Mater Chem A |
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Volume |
8 |
Issue |
35 |
Pages |
18079-18086 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
While graphite has limited capacity as an anode material for potassium-ion batteries, nitrogen-doped carbon materials are more promising as extra capacity can usually be produced. However, the mechanism behind the origin of the extra capacity remains largely unclear. Here, the potassium storage mechanisms have been systematically studied in freestanding and porous N-doped carbon nanofibers with an additional similar to 100 mA h g(-1)discharge capacity at 0.1 A g(-1). The extra capacity is generated in the whole voltage window range from 0.01 to 2 V, which corresponds to both surface/interface K-ion absorptions due to the pyridinic N and pyrrolic N induced atomic vacancies and layer-by-layer intercalation due to the effects of graphitic N. As revealed by transmission electron microscopy, the N-doped samples have a clear and enhanced K-intercalation reaction. Theoretical calculations confirmed that the micropores with pyridinic N and pyrrolic N provide extra sites to form bonds with K, resulting in the extra capacity at high voltage. The chemical absorption of K-ions occurring inside the defective graphitic layer will prompt fast diffusion of K-ions and full realization of the intercalation capacity at low voltage. The approach of preparing N-doped carbon-based materials and the mechanism revealed by this work provide directions for the development of advanced materials for efficient energy storage. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000569873400015 |
Publication Date |
2020-08-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2050-7488; 2050-7496 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.9 |
Times cited |
2 |
Open Access |
OpenAccess |
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Notes |
; F. Liu and J. S. Meng contributed equally to this work. This work was supported by the National Natural Science Foundation of China (51832004 and 51521001), the National Key Research and Development Program of China (2016YFA0202603), and the Natural Science Foundation of Hubei Province (2019CFA001). The S/TEM work was performed at the Nanostructure Research Center (NRC), which is supported by the Fundamental Research Funds for the Central Universities (WUT: 2019III012GX, 2020III002GX), the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, and the State Key Laboratory of Silicate Materials for Architectures (all of the laboratories are at Wuhan University of Technology). ; |
Approved |
Most recent IF: 11.9; 2020 IF: 8.867 |
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Call Number |
UA @ admin @ c:irua:172741 |
Serial |
6573 |
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Permanent link to this record |
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Author |
Coghe, F.; Tirry, W.; Rabet, L.; Schryvers, D.; Van Houtte, P. |
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Title |
Importance of twinning in static and dynamic compression of a Ti-6Al-4V titanium alloy with an equiaxed microstructure |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Materials science and engineering: part A: structural materials: properties, microstructure and processing |
Abbreviated Journal |
Mat Sci Eng A-Struct |
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Volume |
537 |
Issue |
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Pages |
1-10 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Whereas deformation twinning is known to be an important deformation mechanism for hexagonal materials like magnesium and pure titanium, so far almost no literature exists on the twinning behaviour of the Ti-6Al-4V alloy. In this work it was shown that the activation of twinning as a deformation mechanism could have a pronounced effect on the mechanical behaviour of the Ti-6Al-4V alloy. This effect is even more pronounced under dynamic loading conditions. Transmission electron microscopy showed that only the {1 0 1 2}{1 0 1 1} tensile twin system was activated under certain loading conditions. Light-optical microscopy and electron backscatter diffraction data were afterwards used to experimentally determine the twin fractions. The importance of twinning for the texture evolution was also studied. It was shown that even small twin fractions can lead to distinct texture features, especially due to the discrete reorientation of the c-axes. The experimental results were compared to simulated results that were obtained with a viscoplastic self-consistent crystal plasticity code, after experimental validation that twinning can be reliably modelled as a unidirectional slip system. Although good agreement was obtained for the experimental and simulated stress-strain curves, the simulated results concerning twinning correlated well only on a qualitative basis as the simulated twin fractions were systematically higher than the experimental fractions. This seems to strengthen the hypothesis made by other research groups that complete grains might reorient by twinning. (C) 2011 Elsevier B.V. All rights reserved. |
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Place of Publication |
Lausanne |
Editor |
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Language |
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Wos |
000301473300001 |
Publication Date |
2011-12-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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ISSN |
0921-5093; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.094 |
Times cited |
35 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.094; 2012 IF: 2.108 |
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Call Number |
UA @ lucian @ c:irua:97818 |
Serial |
1565 |
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Permanent link to this record |
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Author |
Xu, W.; Peeters, F.M.; Devreese, J.T. |
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Title |
Electrophonon resonances in a quasi-two-dimensional electron system |
Type |
A1 Journal article |
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Year |
1993 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
48 |
Issue |
3 |
Pages |
1562-1570 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems |
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Abstract |
When the energy difference between two electric subbands in a quasi-two-dimensional electron system equals a LO-phonon energy, resonant scattering will occur. This leads to an enhancement of the scattering rate and, consequently, to a suppression of the conductivity. Changing the energy difference between the electric subbands (e.g., through a gate) leads to a series of electrophonon resonances in the conductivity. A detailed study is made of this effect for different confinement potentials. We found that the scattering processes where the emission of a phonon is involved are very important for the electrophonon resonance and that the size of the effect decreases with increasing temperature. |
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Address |
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Corporate Author |
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Thesis |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
A1993LP05000024 |
Publication Date |
2002-07-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0163-1829;1095-3795; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.736 |
Times cited |
45 |
Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ lucian @ c:irua:5747 |
Serial |
1022 |
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Permanent link to this record |
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Author |
Moldovan, D.; Peeters, F.M. |
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Title |
Atomic Collapse in Graphene |
Type |
P1 Proceeding |
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Year |
2016 |
Publication |
Nanomaterials For Security |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
3-17 |
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Keywords |
P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
When the charge Z of an atom exceeds the critical value of 170, it will undergo a process called atomic collapse which triggers the spontaneous creation of electron-positron pairs. The high charge requirements have prevented the observation of this phenomenon with real atomic nuclei. However, thanks to the relativistic nature of the carriers in graphene, the same physics is accessible at a much lower scale. The atomic collapse analogue in graphene is realized using artificial nuclei which can be created via the deposition of impurities on the surface of graphene or using charged vacancies. These supercritically charged artificial nuclei trap electrons in a sequence of quasi-bound states which can be observed experimentally as resonances in the local density of states. |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
Dordrecht |
Editor |
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Language |
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Wos |
000386506200001 |
Publication Date |
2016-07-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
978-94-017-7593-9; 978-94-017-7591-5 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
|
Times cited |
3 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:138237 |
Serial |
4348 |
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Permanent link to this record |
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Author |
Mulkers, J.; Milošević, M.V.; Van Waeyenberge, B. |
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Title |
Cycloidal versus skyrmionic states in mesoscopic chiral magnets |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
93 |
Issue |
93 |
Pages |
214405 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
When subjected to the interfacially induced Dzyaloshinskii-Moriya interaction, the ground state in thin ferromagnetic films with high perpendicular anisotropy is cycloidal. The period of this cycloidal state depends on the strength of the Dzyaloshinskii-Moriya interaction. In this work, we have studied the effect of confinement on the magnetic ground state and excited states, and we determined the phase diagram of thin strips and thin square platelets by means of micromagnetic calculations. We show that multiple cycloidal states with different periods can be stable in laterally confined films, where the period of the cycloids does not depend solely on the Dzyaloshinskii-Moriya interaction strength but also on the dimensions of the film. The more complex states comprising skyrmions are also found to be stable, though with higher energy. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000377298600006 |
Publication Date |
2016-06-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
28 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
c:irua:133919 |
Serial |
4081 |
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Permanent link to this record |
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Author |
Figuerola, A.; Franchini, I.R.; Fiore, A.; Mastria, R.; Falqui, A.; Bertoni, G.; Bals, S.; Van Tendeloo, G.; Kudera, S.; Cingolani, R.; Manna, L. |
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Title |
End-to-end assembly of shape-controlled nanocrystals via a nanowelding approach mediated by gold domains |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Advanced materials |
Abbreviated Journal |
Adv Mater |
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Volume |
21 |
Issue |
5 |
Pages |
550-554 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Welding nanocrystals for assembly: The welding of Au domains grown on the tips of shape-controlled cadmium chalcogenide colloidal nanocrystals is used as a strategy for their assembly. Iodine-induced coagulation of selectively grown Au domains leads to assemblies such as flowerlike structures based on bullet-shaped nanocrystals, linear and cross-linked chains of nanorods, and globular networks with tetrapods as building blocks. |
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Corporate Author |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000263371800005 |
Publication Date |
2008-11-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0935-9648; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
19.791 |
Times cited |
110 |
Open Access |
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Notes |
Esteem 026019; Fwo |
Approved |
Most recent IF: 19.791; 2009 IF: 8.379 |
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Call Number |
UA @ lucian @ c:irua:75960 |
Serial |
1037 |
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Permanent link to this record |
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Author |
Li, Z.; Covaci, L.; Marsiglio, F. |
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Title |
Impact of Dresselhaus versus Rashba spin-orbit coupling on the Holstein polaron |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
20 |
Pages |
205112-205112,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We utilize an exact variational numerical procedure to calculate the ground-state properties of a polaron in the presence of Rashba and linear Dresselhaus spin-orbit coupling. We find that when the linear Dresselhaus spin-orbit coupling approaches the Rashba spin-orbit coupling, the Van Hove singularity in the density of states will be shifted away from the bottom of the band and finally disappear when the two spin-orbit couplings are tuned to be equal. The effective mass will be suppressed; the trend will become more significant for low phonon frequency. The presence of two dominant spin-orbit couplings will make it possible to tune the effective mass with more varied observables. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000303794900003 |
Publication Date |
2012-05-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
18 |
Open Access |
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|
Notes |
; This work was supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC), by ICORE (Alberta), by the Flemish Science Foundation (FWO-Vl), and by the Canadian Institute for Advanced Research (CIfAR). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:99121 |
Serial |
1558 |
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Permanent link to this record |
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Author |
Li, Z.; Covaci, L.; Berciu, M.; Baillie, D.; Marsiglio, F. |
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Title |
Impact of spin-orbit coupling on the Holstein polaron |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
83 |
Issue |
19 |
Pages |
195104-195104,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We utilize an exact variational numerical procedure to calculate the ground state properties of a polaron in the presence of a Rashba-like spin-orbit interaction. Our results corroborate previous work performed with the momentum average approximation and with weak-coupling perturbation theory. We find that spin-orbit coupling increases the effective mass in the regime with weak electron-phonon coupling, and decreases the effective mass in the regimes of intermediate and strong electron-phonon coupling. Analytical strong-coupling perturbation theory results confirm our numerical results in the small-polaron regime. A large amount of spin-orbit coupling can lead to a significant lowering of the polaron effective mass. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000290162500001 |
Publication Date |
2011-05-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
9 |
Open Access |
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|
Notes |
; This work was supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC), by ICORE (Alberta), by Alberta Ingenuity, by the Flemish Science Foundation (FWO-Vl), and by the Canadian Institute for Advanced Research (CIfAR). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:89718 |
Serial |
1561 |
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Permanent link to this record |
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Author |
Sarmadian, N.; Saniz, R.; Lamoen, D.; Partoens, B. |
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Title |
Influence of Al concentration on the optoelectronic properties of Al-doped MgO |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
20 |
Pages |
205129-5 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
We use density functional theory within the local density approximation to investigate the structural, electronic, and optical properties of Al-doped MgO. The concentrations considered range from 6% to 56%. In the latter case, we also compare the optical properties of the amorphous and crystalline phases. We find that, overall, the electronic properties of the crystalline phases change qualitatively little with Al concentration. On the other hand, the changes in the electronic structure in the amorphous phase are more important, most notably because of deep impurity levels in the band gap that are absent in the crystalline phase. This leads to observable effects in, e.g., the optical absorption edge and in the refractive index. Thus, the latter can be used to characterize the crystalline to amorphous transition with Al doping level. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000311605000003 |
Publication Date |
2012-11-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
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Notes |
Iwt; Fwo |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:105137 |
Serial |
1612 |
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Permanent link to this record |
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Author |
Li, L.L.; Xu, W.; Peeters, F.M. |
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Title |
Intrinsic optical anisotropy of [001]-grown short-period InAs/GaSb superlattices |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
82 |
Issue |
23 |
Pages |
235422-235422,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We theoretically investigate the intrinsic optical anisotropy or polarization induced by the microscopic interface asymmetry (MIA) in no-common-atom (NCA) InAs/GaSb superlattices (SLs) grown along the [001] direction. The eight-band K⋅P model is used to calculate the electronic band structures and incorporates the MIA effect. A Boltzmann equation approach is employed to calculate the optical properties. We found that in NCA InAs/GaSb SLs, the MIA effect causes a large in-plane optical anisotropy for linearly polarized light and the largest anisotropy occurs for light polarized along the [110] and [11̅ 0] directions. The relative difference between the optical-absorption coefficient for [110]-polarized light and that for [11̅ 0]-polarized light is found to be larger than 50%. The dependence of the in-plane optical anisotropy on temperature, photoexcited carrier density, and layer width is examined in detail. This study is important for optical devices which require the polarization control and selectivity. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000286768800007 |
Publication Date |
2010-12-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
18 |
Open Access |
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Notes |
; This work was supported partly by the Flemish Science Foundation (FWO-VL), the Belgium Science Policy (IAP), the NSF of China (Grants No. 10664006, No. 10504036, and No. 90503005), Special Funds of 973 Project of China (Grant No. 2005CB623603), and Knowledge Innovation Program of the Chinese Academy of Sciences. ; |
Approved |
Most recent IF: 3.836; 2010 IF: 3.774 |
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Call Number |
UA @ lucian @ c:irua:88909 |
Serial |
1717 |
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Permanent link to this record |
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Author |
Vodolazov, D.Y.; Peeters, F.M. |
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Title |
Enhancement of the retrapping current of superconducting microbridges of finite length |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
2 |
Pages |
024508-024508,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We theoretically find that the resistance of a superconducting microbridge or nanowire decreases while the retrapping current I(r) for the transition to the superconducting state increases when one suppresses the magnitude of the order parameter vertical bar Delta vertical bar in the attached superconducting leads. This effect is a consequence of the increased energy interval for diffusion of the “hot” nonequilibrium quasiparticles (induced by the oscillations of vertical bar Delta vertical bar in the center of the microbridge) to the leads. The effect is absent in short microbridges (with length less than the coherence length) and it is relatively weak in long microbridges (with length larger than the inelastic relaxation length of the nonequilibrium distribution function). A nonmonotonous dependence of I(r) on the length of the microbridge is predicted. Our results are important for the explanation of the enhancement of the critical current and the appearance of negative magnetoresistance observed in many recent experiments on superconducting microbridges or nanowires. |
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Place of Publication |
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Editor |
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Language |
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Wos |
000298863400005 |
Publication Date |
2012-01-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
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Notes |
; This work was supported by the Russian Foundation for Basic Research, Russian Agency of Education, under the Federal Target Programme “Scientific and Educational Personnel of Innovative Russia in 2009-2013” and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:96235 |
Serial |
1065 |
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Permanent link to this record |