| |
Records |
Links |
|
Author |
Komendová, L.; Chen, Y.; Shanenko, A.A.; Milošević, M.V.; Peeters, F.M. |
|
| |
Title |
Two-band superconductors : hidden criticality deep in the superconducting state |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
|
| |
Volume |
108 |
Issue |
20 |
Pages |
207002-207002,5 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We show that two-band superconductors harbor hidden criticality deep in the superconducting state, stemming from the critical temperature of the weaker band taken as an independent system. For sufficiently small interband coupling gamma the coherence length of the weaker band exhibits a remarkable deviation from the conventional monotonic increase with temperature, namely, a pronounced peak close to the hidden critical point. The magnitude of the peak scales as proportional to gamma(-mu), with the Landau critical exponent mu = 1/3, the same as found for the mean-field critical behavior with respect to the source field in ferromagnets and ferroelectrics. Here reported hidden criticality of multiband superconductors can be experimentally observed by, e.g., imaging of the variations of the vortex core in a broader temperature range. Similar effects are expected for the superconducting multilayers. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
|
| |
Language |
|
Wos |
000304064000017 |
Publication Date  |
2012-05-15 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
8.462 |
Times cited |
75 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). Useful discussions with A. V. Vagov are acknowledged. ; |
Approved |
Most recent IF: 8.462; 2012 IF: 7.943 |
|
| |
Call Number |
UA @ lucian @ c:irua:98945 |
Serial |
3770 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Badalyan, S.M.; Peeters, F.M. |
|
| |
Title |
Effect of nonhomogenous dielectric background on the plasmon modes in graphene double-layer structures at finite temperatures |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
19 |
Pages |
195444-195444,6 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We have calculated the plasmon modes in graphene double layer structures at finite temperatures, taking into account the inhomogeneity of the dielectric background of the system. The effective dielectric function is obtained from the solution of the Poisson equation of a three-layer dielectric medium with graphene sheets located at the interfaces, separating the different materials. Due to the momentum dispersion of the effective dielectric function, the intra- and interlayer bare Coulomb interactions in the graphene double layer system acquires an additional momentum dependence-an effect that is of the order of the interlayer interaction itself. We show that the energies of the in-phase and out-of-phase plasmon modes are determined largely by different values of the spatially dependent effective dielectric function. The effect of the dielectric inhomogeneity increases with temperature, and even at high temperatures the energy shift induced by the dielectric inhomogeneity and temperature itself remains larger than the broadening of the plasmon energy dispersions due to the Landau damping. The obtained new features of the plasmon dispersions can be observed in frictional drag measurements and in inelastic light scattering and electron energy-loss spectroscopies. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000304394800011 |
Publication Date |
2012-05-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
67 |
Open Access |
|
|
| |
Notes |
; We thank G. Vignale for useful discussions and acknowledge support from the Flemisch Science Foundation (FWO-Fl) and the Belgian Science Policy (BELSPO). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:98941 |
Serial |
826 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Neek-Amal, M.; Peeters, F.M. |
|
| |
Title |
Strain-engineered graphene through a nanostructured substrate : 1 : deformations |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
19 |
Pages |
195445-195445,11 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Using atomistic simulations we investigate the morphological properties of graphene deposited on top of a nanostructured substrate. Sinusoidally corrugated surfaces, steps, elongated trenches, one-dimensional and cubic barriers, spherical bubbles, Gaussian bumps, and Gaussian depressions are considered as support structures for graphene. The graphene-substrate interaction is governed by van der Waals forces and the profile of the graphene layer is determined by minimizing the energy using molecular dynamics simulations. Based on the obtained optimum configurations, we found that (i) for graphene placed over sinusoidally corrugated substrates with corrugation wavelengths longer than 2 nm, the graphene sheet follows the substrate pattern while for supported graphene it is always suspended across the peaks of the substrate, (ii) the conformation of graphene to the substrate topography is enhanced when increasing the energy parameter in the van der Waals model, (iii) the adhesion of graphene into the trenches depends on the width of the trench and on the graphene's orientation, i. e., in contrast to a small-width (3 nm) nanoribbon with armchair edges, the one with zigzag edges follows the substrate profile, (iv) atomic-scale graphene follows a Gaussian bump substrate but not the substrate with a Gaussian depression, and (v) the adhesion energy due to van der Waals interaction varies in the range [0.1-0.4] J/m(2). |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000304394800012 |
Publication Date |
2012-05-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
62 |
Open Access |
|
|
| |
Notes |
; We thank L. Covaci and S. Costamagna for valuable comments. We acknowledge M. Zarenia, M. R. Masir and D. Nasr for fruitful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl) and ESF EUROCORE program EuroGRAPHENE: CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:98942 |
Serial |
3166 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Neek-Amal, M.; Peeters, F.M. |
|
| |
Title |
Strain-engineered graphene through a nanostructured substrate : 2 : pseudomagnetic fields |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
19 |
Pages |
195446-195446,6 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The strain-induced pseudomagnetic field in supported graphene deposited on top of a nanostructured substrate is investigated by using atomistic simulations. A step, an elongated trench, a one-dimensional barrier, a spherical bubble, a Gaussian bump, and a Gaussian depression are considered as support structures for graphene. From the obtained optimum configurations we found very strong induced pseudomagnetic fields which can reach up to similar to 1000 T due to the strain-induced deformations in the supported graphene. Different magnetic confinements with controllable geometries are found by tuning the pattern of the substrate. The resulting induced magnetic fields for graphene on top of a step, barrier, and trench are calculated. In contrast to the step and trench the middle part of graphene on top of a barrier has zero pseudomagnetic field. This study provides a theoretical background for designing magnetic structures in graphene by nanostructuring substrates. We found that altering the radial symmetry of the deformation changes the sixfold symmetry of the induced pseudomagnetic field. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000304394800013 |
Publication Date |
2012-05-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
31 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the ESF EUROCORE program EuroGRAPHENE: CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:98943 |
Serial |
3167 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Ramos, I.R.O.; Ferreira, W.P.; Munarin, F.F.; Farias, G.A.; Peeters, F.M. |
|
| |
Title |
Bilayer crystals of charged magnetic dipoles : structure and phonon spectrum |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : E : statistical, nonlinear, and soft matter physics |
Abbreviated Journal |
Phys Rev E |
|
| |
Volume |
85 |
Issue |
5:1 |
Pages |
051404-051404,12 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We study the structure and phonon spectrum of a two-dimensional bilayer system of classical charged dipoles oriented perpendicular to the plane of the layers for equal density in each layer. This system can be tuned through six different crystalline phases by changing the interlayer separation or the charge and/or dipole moment of the particle. The presence of the charge on the dipole particles is responsible for the nucleation of five staggered phases and a disordered phase which are not found in the magnetic dipole bilayer system. These extra phases are a consequence of the competition between the repulsive Coulomb and the attractive dipole interlayer interaction. We present the phase diagram and determine the order of the phase transitions. The phonon spectrum of the system was calculated within the harmonic approximation, and a nonmonotonic behavior of the phonon spectrum is found as a function of the effective strength of the interparticle interaction. The stability of the different phases is determined. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Institute of Physics |
Place of Publication |
Woodbury (NY) |
Editor |
|
|
| |
Language |
|
Wos |
000304403400002 |
Publication Date |
2012-05-30 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1539-3755;1550-2376; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.366 |
Times cited |
8 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Brazilian agencies CNPq, CAPES, and FUNCAP (PRONEX grant), the Flemish Science Foundation (FWO-Vl), the bilateral program between Flanders and Brazil, and the CNPq-FWO collaborating project. The authors are grateful to Prof. G. Goldoni for some technical clarifications concerning Ref. [18]. ; |
Approved |
Most recent IF: 2.366; 2012 IF: 2.313 |
|
| |
Call Number |
UA @ lucian @ c:irua:98940 |
Serial |
233 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Badalyan, S.M.; Peeters, F.M. |
|
| |
Title |
Electron-phonon bound state in graphene |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
20 |
Pages |
205453-205453,5 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The fine structure of the Dirac energy spectrum in graphene induced by electron-optical phonon coupling is investigated in the portion of the spectrum near the phonon emission threshold. The derived new dispersion equation in the immediate neighborhood below the threshold corresponds to an electron-phonon bound state. We find that the singular vertex corrections beyond perturbation theory strongly increase the electron-phonon binding energy scale. The predicted enhancement of the effective electron-phonon coupling can be measured using angle-resolved spectroscopy. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000304649400002 |
Publication Date |
2012-05-30 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
12 |
Open Access |
|
|
| |
Notes |
; We thank E. Rashba for the useful discussion and acknowledge support from the Belgian Science Policy (IAP) and BELSPO. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:98939 |
Serial |
982 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Krstajić, P.M.; Peeters, F.M. |
|
| |
Title |
Energy-momentum dispersion relation of plasmarons in graphene |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
20 |
Pages |
205454-205454,4 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The many-body correction to the band structure of a quasi-free-standing graphene layer is obtained within the Overhauser approach, where the electron-plasmon interaction is described as a field theoretical problem. We find that the Dirac-like spectrum is shifted by Delta E(k = 0), which is on the order of 50-150 meV, depending on the electron concentration n(e), and is in semiquantitative agreement with experimental data. The value of the Fermi velocity is renormalized by several percents and decreases with increasing electron concentration as found experimentally. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000304649900004 |
Publication Date |
2012-06-05 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
11 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the ESF-EuroGRAPHENE project CON-GRAN, and the Serbian Ministry of Education and Science (project No. TR 32008). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:98937 |
Serial |
1043 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Costamagna, S.; Schulz, A.; Covaci, L.; Peeters, F. |
|
| |
Title |
Partially unzipped carbon nanotubes as magnetic field sensors |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
|
| |
Volume |
100 |
Issue |
23 |
Pages |
232104-232104,3 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The conductance through graphene nanoribbons (GNR) connected to a partially unzipped carbon nanotube (CNT) is studied in the presence of an external magnetic field applied parallel to the long axis of the tube by means of non-equilibrium Green's function technique. We consider CNTs that are partially unzipped to form armchair-GNR/zigzag-CNT/armchair-GNR or zigzag-GNR/armchair-CNT/zigzag-GNR junctions. We find that the inclusion of a longitudinal magnetic field affects the electronic states only in the CNT region, leading to the suppression of the conductance at low energies. We demonstrate that both types of junctions can be used as magnetic field sensors. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4726039] |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
|
| |
Language |
|
Wos |
000305089900038 |
Publication Date |
2012-06-07 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.411 |
Times cited |
10 |
Open Access |
|
|
| |
Notes |
; L.C. acknowledges support from the Flemish Science Foundation (FWO-Vl) and S.C. from the Belgian Science Foundation (BELSPO). This work is supported by the ESF-EuroGRAPHENE Project CONGRAN. ; |
Approved |
Most recent IF: 3.411; 2012 IF: 3.794 |
|
| |
Call Number |
UA @ lucian @ c:irua:99083 |
Serial |
2556 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Chen, Y.; Shanenko, A.A.; Croitoru, M.D.; Peeters, F.M. |
|
| |
Title |
Quantum cascades in nano-engineered superconductors : geometrical, thermal and paramagnetic effects |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
|
| |
Volume |
24 |
Issue |
26 |
Pages |
265702 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The effect of a parallel magnetic field on the orbital motion of electrons in high-quality superconducting nanowires resulting in a superconductor-to-normal transition which occurs through a cascade of jumps in the order parameter as a function of the magnetic field. Such cascades originate from the transverse size quantization that splits the conduction band into a series of subbands. Here, based on a numerical solution of the Bogoliubov-de Gennes equations for a hollow nanocylinder, we investigate how the quantum-size cascades depend on the confining geometry, i.e., by changing the cylinder radius R and its thickness d we cover the range from the nanowire-like to the nanofilm-like regime. The cascades are shown to become much less pronounced when increasing R/d, i.e., when the nanofilm-like regime is approached. When the temperature is non-zero they are thermally smoothed. This includes the spin-magnetic-field interaction which reduces the critical (depairing) parallel magnetic field H-c,H-parallel to but does not have any qualitative effect on the quantum cascades. From our calculations it is seen that the paramagnetic limiting field H-par significantly exceeds H-c,H-parallel to even in extremely narrow nanocylinders, i.e., when R, d are down to a few nanometers, and H-c,H-parallel to is only about 10% larger when switching-off the spin-magnetic-field interaction in this case. Both characteristic fields, H-c,H-parallel to and H-par, exhibit pronounced quantum-size oscillations. We demonstrate that the quantum cascades and the quantum-size oscillations survive in the presence of surface roughness. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
000305640800014 |
Publication Date |
2012-06-07 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.649 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI) and the ESF-AQDJJ network. MDC acknowledges the support of the EU Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR). ; |
Approved |
Most recent IF: 2.649; 2012 IF: 2.355 |
|
| |
Call Number |
UA @ lucian @ c:irua:100281 |
Serial |
2773 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Pogosov, W.V.; Misko, V.R. |
|
| |
Title |
Vortex quantum tunneling versus thermal activation in ultrathin superconducting nanoislands |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
22 |
Pages |
224508-224508,5 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We consider two possible mechanisms for single-vortex fluctuative entry/exit through the surface barrier in ultrathin superconducting disk-shaped nanoislands made of Pb and consisting of just a few monoatomic layers, which can be fabricated using modern techniques. We estimate tunneling probabilities and establish criteria for the crossover between these two mechanisms depending on magnetic field and system sizes. For the case of vortex entry, quantum tunneling dominates on the major part of the temperature/flux phase diagram. For the case of vortex exit, thermal activation turns out to be more probable. This nontrivial result is due to the subtle balance between the barrier height and width, which determine rates of the thermal activation and quantum tunneling, respectively. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000304856600003 |
Publication Date |
2012-06-07 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
2 |
Open Access |
|
|
| |
Notes |
; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). W. V. P. acknowledges numerous discussions with A. O. Sboychakov and the support from the Dynasty Foundation, the RFBR (Project No. 12-02-00339), and RFBR-CNRS programme (Project No. 12-02-91055). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:98908 |
Serial |
3882 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Bals, S.; Van Aert, S.; Romero, C.P.; Lauwaet, K.; Van Bael, M.J.; Schoeters, B.; Partoens, B.; Yuecelen, E.; Lievens, P.; Van Tendeloo, G. |
|
| |
Title |
Atomic scale dynamics of ultrasmall germanium clusters |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
|
| |
Volume |
3 |
Issue |
897 |
Pages |
897 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
Starting from the gas phase, small clusters can be produced and deposited with huge flexibility with regard to composition, materials choice and cluster size. Despite many advances in experimental characterization, a detailed morphology of such clusters is still lacking. Here we present an atomic scale observation as well as the dynamical behaviour of ultrasmall germanium clusters. Using quantitative scanning transmission electron microscopy in combination with ab initio calculations, we are able to characterize the transition between different equilibrium geometries of a germanium cluster consisting of less than 25 atoms. Seven-membered rings, trigonal prisms and some smaller subunits are identified as possible building blocks that stabilize the structure. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000306099900024 |
Publication Date |
2012-06-12 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2041-1723; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
12.124 |
Times cited |
90 |
Open Access |
|
|
| |
Notes |
Fwo; Iap; Iwt |
Approved |
Most recent IF: 12.124; 2012 IF: 10.015 |
|
| |
Call Number |
UA @ lucian @ c:irua:100340 |
Serial |
183 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Čukarić, N.; Arsoski, V.; Tadić, M.; Peeters, F.M. |
|
| |
Title |
Hole states in nanocups in a magnetic field |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
23 |
Pages |
235425-235425,11 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The magnetic-field dependence of the hole states in a nanocup, which is composed of a ring (the nanocup rim) that surrounds a disk (the nanocup bottom), is obtained within the Luttinger-Kohn model for the unstrained GaAs/(Al,Ga) As and the strained (In,Ga) As/GaAs systems. Aharonov-Bohm oscillations due to angular momentum transitions of the hole ground state appear with periods that vary with the thickness of the disk. The strain in the (In, Ga) As/GaAs nanocup is sensitive to the disk thickness and favors the spatial localization of the heavy holes inside the disk. Therefore, the angular momentum transitions between the valence-band states disappear for much thinner disks than in the case of the unstrained GaAs/(Al, Ga) As nanocups. In both systems, the oscillations in the energy of the hole ground state are found to disappear for thinner inner layer than in the electron ground-state energy. This is due to the different confining potentials and the mixing between the heavy- and light-hole states. As a consequence, magnetization of the single hole is found to strongly depend on the bottom thickness of the strained (In, Ga) As/GaAs nanocup. Furthermore, we found that the strain can lead to a spatial separation of the electron and the hole, as in type-II band alignment, which is advantageous for the appearance of the excitonic Aharonov-Bohm effect. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000305116700005 |
Publication Date |
2012-06-14 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
|
|
| |
Notes |
; The authors thank B. Partoens for useful discussions. This work was supported by the EU NoE: SANDiE, the Ministry of Education and Science of Serbia, and the Belgian Science Policy (IAP). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:98906 |
Serial |
1477 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zarenia, M.; Vasilopoulos, P.; Peeters, F.M. |
|
| |
Title |
Magnetotransport in periodically modulated bilayer graphene |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
24 |
Pages |
245426-245426,10 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Magnetotransport in bilayer graphene in the presence of a weak and periodic potential is investigated in the presence of a perpendicular magnetic field B. The modulation broadens the Landau levels into bands and for weak magnetic fields leads to the well-known Weiss oscillations in their bandwidth and their transport coefficients at very low B and to the Shubnikov-de Haas oscillations at larger B. The amplitude of the Weiss oscillations is severely reduced if the periodic potentials applied to the two layers oscillate out of phase. We also contrast some results with those corresponding to single-layer graphene. Relative to them the flat-band condition and the oscillation amplitude differ substantially, due to the interlayer coupling, and agree only when this coupling is extremely weak. We further show that the Hall conductivity exhibits the well-known steps at half-integer and integer multiples of 4e(2)/h in single-layer and bilayer graphene, respectively, even for very weak magnetic fields. The results are pertinent to weak and periodic corrugations when the potential modulation dominates the strain-induced magnetic modulation. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000305253600012 |
Publication Date |
2012-06-14 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
21 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES program EuroGRAPHENE (project CON-GRAN), and the Canadian NSERC Grant No. OGP0121756. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:99077 |
Serial |
1934 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Chen, Y.; Shanenko, A.A.; Peeters, F.M. |
|
| |
Title |
Superconducting transition temperature of Pb nanofilms : impact of thickness-dependent oscillations of the phonon-mediated electron-electron coupling |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
85 |
Issue |
22 |
Pages |
224517-224517,6 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
To date, several experimental groups reported measurements of the thickness dependence of T-c of atomically uniform single-crystalline Pb nanofilms. The reported amplitude of the T-c oscillations varies significantly from one experiment to another. Here we propose that the reason for this unresolved issue is an interplay of the quantum-size variations in the single-electron density of states with thickness-dependent oscillations in the phonon-mediated electron-electron coupling. Such oscillations in the coupling depend on the substrate material, the quality of the interface, the protection cover, and other details of the fabrication process, changing from one experiment to another. This explains why the available data do not exhibit one-voice consistency about the amplitude of the T-c oscillations. Our analyses are based on a numerical solution of the Bogoliubov-de Gennes equations for a superconducting slab. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000305251300006 |
Publication Date |
2012-06-14 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
24 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:99076 |
Serial |
3368 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Croitoru, M.D.; Shanenko, A.A.; Kaun, C.C.; Peeters, F.M. |
|
| |
Title |
Ultra-small metallic grains : effect of statistical fluctuations of the chemical potential on superconducting correlations and vice versa |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
|
| |
Volume |
24 |
Issue |
27 |
Pages |
275701 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Superconducting correlations in an isolated metallic grain are governed by the interplay between two energy scales: the mean level spacing delta and the bulk pairing gap Delta(0), which are strongly influenced by the position of the chemical potential with respect to the closest single-electron level. In turn superconducting correlations affect the position of the chemical potential. Within the parity projected BCS model we investigate the probability distribution of the chemical potential in a superconducting grain with randomly distributed single-electron levels. Taking into account statistical fluctuations of the chemical potential due to the pairing interaction, we find that such fluctuations have a significant impact on the critical level spacing delta(c) at which the superconducting correlations cease: the critical ratio delta(c)/Delta(0) at which superconductivity disappears is found to be increased. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
000305653100012 |
Publication Date |
2012-06-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.649 |
Times cited |
9 |
Open Access |
|
|
| |
Notes |
; This work was supported by the European Community under the Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR), the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF network INSTANS. MDC and AAS are grateful to A Vagov for stimulating discussions. ; |
Approved |
Most recent IF: 2.649; 2012 IF: 2.355 |
|
| |
Call Number |
UA @ lucian @ c:irua:100280 |
Serial |
3793 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zhao, H.J.; Misko, V.R.; Peeters, F.M. |
|
| |
Title |
Analysis of pattern formation in systems with competing range interactions |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
New journal of physics |
Abbreviated Journal |
New J Phys |
|
| |
Volume |
14 |
Issue |
|
Pages |
063032 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We analyzed pattern formation and identified various morphologies in a system of particles interacting through a non-monotonic potential with a competing range interaction characterized by a repulsive core (r < r(c)) and an attractive tail (r > r(c)), using molecular-dynamics simulations. Depending on parameters, the interaction potential models the inter-particle interaction in various physical systems ranging from atoms, molecules and colloids to vortices in low kappa type-II superconductors and in recently discovered 'type-1.5' superconductors. We constructed a 'morphology diagram' in the plane 'critical radius r(c)-density n' and proposed a new approach to characterizing the different types of patterns. Namely, we elaborated a set of quantitative criteria in order to identify the different pattern types, using the radial distribution function (RDF), the local density function and the occupation factor. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Bristol |
Editor |
|
|
| |
Language |
|
Wos |
000306946600003 |
Publication Date |
2012-06-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1367-2630; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.786 |
Times cited |
45 |
Open Access |
|
|
| |
Notes |
; We acknowledge useful discussions with Ernst Helmut Brandt, Charles Reichhardt and Cynthia Olson Reichhardt. This work was supported by the 'Odysseus' Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.786; 2012 IF: 4.063 |
|
| |
Call Number |
UA @ lucian @ c:irua:101140 |
Serial |
102 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Kao, K.-H.; Verhulst, A.S.; Vandenberghe, W.G.; Sorée, B.; Magnus, W.; Leonelli, D.; Groeseneken, G.; De Meyer, K. |
|
| |
Title |
Optimization of gate-on-source-only tunnel FETs with counter-doped pockets |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
IEEE transactions on electron devices |
Abbreviated Journal |
Ieee T Electron Dev |
|
| |
Volume |
59 |
Issue |
8 |
Pages |
2070-2077 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We investigate a promising tunnel FET configuration having a gate on the source only, which is simultaneously exhibiting a steeper subthreshold slope and a higher ON-current than the lateral tunneling configuration with a gate on the channel. Our analysis is performed based on a recently developed 2-D quantum-mechanical simulator calculating band-to-band tunneling and including quantum confinement (QC). It is shown that the two disadvantages of the structure, namely, the sensitivity to gate alignment and the physical oxide thickness, are mitigated by placing a counter-doped parallel pocket underneath the gate-source overlap. The pocket also significantly reduces the field-induced QC. The findings are illustrated with all-Si and all-Ge gate-on-source-only tunnel field-effect transistor simulations. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
|
| |
Language |
|
Wos |
000306920200011 |
Publication Date |
2012-06-27 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0018-9383;1557-9646; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.605 |
Times cited |
72 |
Open Access |
|
|
| |
Notes |
; Manuscript received February 17, 2012; revised May 7, 2012; accepted May 11, 2012. Date of publication June 26, 2012; date of current version July 19, 2012. This work was supported by the Interuniversity Microelectronics Center's Industrial Affiliation Program. The work of W. G. Vandenberghe was supported by the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen) through a Ph.D. stipend. The review of this paper was arranged by Editor H. S. Momose. ; |
Approved |
Most recent IF: 2.605; 2012 IF: 2.062 |
|
| |
Call Number |
UA @ lucian @ c:irua:100820 |
Serial |
2487 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Berdiyorov, G.R.; Milošević, M.V.; Peeters, F.M. |
|
| |
Title |
Spatially dependent sensitivity of superconducting meanders as single-photon detectors |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
|
| |
Volume |
100 |
Issue |
26 |
Pages |
262603 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The photo-response of a thin current-carrying superconducting stripe with a 90 degrees turn is studied within the time-dependent Ginzburg-Landau theory. We show that the photon acting near the inner corner (where the current density is maximal due to the current crowding [J. R. Clem and K. K. Berggren, Phys. Rev. B 84, 174510 (2011)]) triggers the nucleation of superconducting vortices at currents much smaller than the expected critical one, but does not bring the system to a higher resistive state and thus remains undetected. The transition to the resistive state occurs only when the photon hits the stripe away from the corner due to there uniform current distribution across the sample, and dissipation is due to the nucleation of a kinematic vortex-antivortex pair near the photon incidence. We propose strategies to account for this problem in the measurements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4731627] |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
|
| |
Language |
|
Wos |
000305831500057 |
Publication Date |
2012-06-28 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.411 |
Times cited |
27 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI). G. R. B. acknowledges individual support from FWO-VI. ; |
Approved |
Most recent IF: 3.411; 2012 IF: 3.794 |
|
| |
Call Number |
UA @ lucian @ c:irua:100336 |
Serial |
3066 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Pathangi, H.; Cherman, V.; Khaled, A.; Sorée, B.; Groeseneken, G.; Witvrouw, A. |
|
| |
Title |
Towards CMOS-compatible single-walled carbon nanotube resonators |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Microelectronic engineering |
Abbreviated Journal |
Microelectron Eng |
|
| |
Volume |
107 |
Issue |
|
Pages |
219-222 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We report a totally CMOS-compatible fabrication technique to assemble horizontally suspended single-walled carbon nanotube (SWCNT) resonators. Individual SWCNTs are assembled in parallel at multiple sites by a technique called dielectrophoresis. The mechanical resonance frequencies of the suspended SWCNTs are in the range of 2035 MHz as determined from the piezoresistive response of the resonators during electrostatic actuation. The resistance of the suspended SWCNT either remains unchanged or increases or decreases significantly as a function of the actuation frequency. This can be explained by the effect the nanotube chirality has on the piezoresistive gauge factor. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
|
| |
Language |
|
Wos |
000319855800040 |
Publication Date |
2012-07-02 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0167-9317; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.806 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
; ; |
Approved |
Most recent IF: 1.806; 2013 IF: 1.338 |
|
| |
Call Number |
UA @ lucian @ c:irua:109260 |
Serial |
3685 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Neek-Amal, M.; Covaci, L.; Peeters, F.M. |
|
| |
Title |
Nanoengineered nonuniform strain in graphene using nanopillars |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
86 |
Issue |
4 |
Pages |
041405 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Recent experiments showed that nonuniform strain can be produced by depositing graphene over pillars. We employed atomistic calculations to study the nonuniform strain and the induced pseudomagnetic field in graphene on top of nanopillars. By decreasing the distance between the nanopillars a complex distribution for the pseudomagnetic field can be generated. Furthermore, we performed tight-binding calculations of the local density of states (LDOS) by using the relaxed graphene configuration obtained from atomistic calculations. We find that the quasiparticle LDOS are strongly modified near the pillars, both at low energies showing sublattice polarization and at high energies showing shifts of the van Hove singularity. Our study shows that changing the specific pattern of the nanopillars allows us to create a desired shape of the pseudomagnetic field profile while the LDOS maps provide an input for experimental verification by scanning tunneling microscopy. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000306313900001 |
Publication Date |
2012-07-14 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
51 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-V1) and the EuroGRAPHENE project CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:100765 |
Serial |
2255 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Pina, J.C.; de Souza Silva, C.C.; Milošević, M.V. |
|
| |
Title |
Stability of fractional vortex states in a two-band mesoscopic superconductor |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
86 |
Issue |
2 |
Pages |
024512 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We investigate the stability of noncomposite fractional vortex states in a mesoscopic two-band superconductor within the two-component Ginzburg-Landau model. Our analysis explicitly takes into account the relationship between the model parameters and microscopic material parameters, such as partial density of states, Fermi velocities and elements of the electron-phonon coupling matrix. We have found that states with different phase winding number in each band (L-1 not equal L-2) and fractional flux can exist in many different configurations, including rather unconventional ones where the dominating band carries larger winding number and states where vertical bar L-1 – L-2 vertical bar > 1. We present a detailed analysis of the stability of the observed vortex structures with respect to changing the microscopic parameters, showing that, in the weak coupling case, fractional vortex states can be assessed in essentially the whole range of temperatures and applied magnetic fields in which both bands are active. Finally, we propose an efficient way of increasing the range of parameters for which these fractional vortex states can be stabilized. In particular, our proposal allows for observation of fractional vortex structures in materials with stronger coupling, where those states are forbidden at a homogeneous field. This is accomplished with the help of the stray fields of a suitably prepared magnetic dot placed nearby the superconducting disk. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000306309600006 |
Publication Date |
2012-07-14 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
38 |
Open Access |
|
|
| |
Notes |
; We thank Eric B. Claude, Miguel A. Zorro, and Rogerio M. da Silva for assistance in the development of the numerical code used in our simulations. This work was supported by the Brazilian science agencies CNPq and FACEPE, by the FACEPE/CNPq-PRONEX program, under Grant No. APQ-0589-1.05/08, and by CNPq-FWO Brazil-Flanders co-operation program. M.V.M. acknowledges support from the CAPES-PVE program. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:100766 |
Serial |
3126 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Costamagna, S.; Neek-Amal, M.; Los, J.H.; Peeters, F.M. |
|
| |
Title |
Thermal rippling behavior of graphane |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
86 |
Issue |
4 |
Pages |
041408-4 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Thermal fluctuations of single layer hydrogenated graphene (graphane) are investigated using large scale atomistic simulations. By analyzing the mean square value of the height fluctuations < h(2)> and the height-height correlation function H(q) for different system sizes and temperatures, we show that hydrogenated graphene is an unrippled system in contrast to graphene. The height fluctuations are bounded, which is confirmed by a H(q) tending to a constant in the long wavelength limit instead of showing the characteristic scaling law q(4-eta)(eta similar or equal to 0.85) predicted by membrane theory. This unexpected behavior persists up to temperatures of at least 900 K and is a consequence of the fact that in graphane the thermal energy can be accommodated by in-plane bending modes, i.e., modes involving C-C-C bond angles in the buckled carbon layer, instead of leading to significant out-of-plane fluctuations that occur in graphene. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000306649200002 |
Publication Date |
2012-07-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
46 |
Open Access |
|
|
| |
Notes |
; We thank A. Fasolino, A. Dobry, and K. H. Michel for their useful comments. S.C. is supported by the Belgian Science Foundation (BELSPO). This work is supported by the ESF-EuroGRAPHENE project CONGRAN and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:100840 |
Serial |
3630 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Berdiyorov, G.R.; Milošević, M.V.; Latimer, M.L.; Xiao, Z.L.; Kwok, W.K.; Peeters, F.M. |
|
| |
Title |
Large magnetoresistance oscillations in mesoscopic superconductors due to current-excited moving vortices |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
|
| |
Volume |
109 |
Issue |
5 |
Pages |
057004 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We show in the case of a superconducting Nb ladder that a mesoscopic superconductor typically exhibits magnetoresistance oscillations whose amplitude and temperature dependence are different from those stemming from the Little-Parks effect. We demonstrate that these large resistance oscillations (as well as the monotonic background on which they are superimposed) are due to current-excited moving vortices, where the applied current in competition with the oscillating Meissner currents imposes or removes the barriers for vortex motion in an increasing magnetic field. Because of the ever present current in transport measurements, this effect should be considered in parallel with the Little-Parks effect in low-critical temperature (T-c) samples, as well as with recently proposed thermal activation of dissipative vortex-antivortex pairs in high-T-c samples. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
|
| |
Language |
|
Wos |
000306994900024 |
Publication Date |
2012-07-31 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
8.462 |
Times cited |
65 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP) (theory) and by the U. S. Department of Energy (DOE) Award No. DE-FG02-06ER46334 (experiment). G. R. B. acknowledges individual grant from FWO-Vl. W. K. K. acknowledges support from DOE BES under Contract No. DE-AC02-06CH11357, which also funds Argonne's Center for Nanoscale Materials (CNM) where the focused-ion-beam milling was performed. ; |
Approved |
Most recent IF: 8.462; 2012 IF: 7.943 |
|
| |
Call Number |
UA @ lucian @ c:irua:100832 |
Serial |
1780 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Bousige, C.; Rols, S.; Paineau, E.; Rouziere, S.; Mocuta, C.; Verberck, B.; Wright, J.P.; Kataura, H.; Launois, P. |
|
| |
Title |
Progressive melting in confined one-dimensional C60 chains |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
86 |
Issue |
4 |
Pages |
045446 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
C-60 fullerenes confined inside single-walled carbon nanotubes form an archetypal one-dimensional system. X-ray diffraction experiments, from room temperature to 1073 K, reveal an increasing melting phenomenon. Detailed analysis of the sawtooth peak characteristic of the fullerene organization allows the quantitative determination of fluctuations in intermolecular distances. The present results validate the predictions of one-dimensional statistical models. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000306925300007 |
Publication Date |
2012-08-01 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
|
Open Access |
|
|
| |
Notes |
; ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:100835 |
Serial |
2726 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Matulis, A.; Masir, M.R.; Peeters, F.M. |
|
| |
Title |
Scattering of a Dirac electron on a mass barrier |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : A : atomic, molecular and optical physics |
Abbreviated Journal |
Phys Rev A |
|
| |
Volume |
86 |
Issue |
2 |
Pages |
022101 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The interaction of a wave packet (and in particular the wave front) with a mass barrier is investigated in one dimension. We discuss the main features of the wave packet that are inherent to two-dimensional wave packets, such as compression during reflection, penetration in the case when the energy is lower than the height of the barrier, waving tails, precursors, and the retardation of the reflected and penetrated wave packets. These features depend on the wave-packet envelope function which we demonstrate by considering the case of a rectangular wave packet with sharp front and trailing edges and a smooth Gaussian wave packet. The method of Fourier integral for obtaining the nonstationary solutions is used. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000306991200001 |
Publication Date |
2012-08-01 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1050-2947;1094-1622; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.925 |
Times cited |
9 |
Open Access |
|
|
| |
Notes |
; This research was supported by the Flemish Science Foundation (FWO-Vl) and (in part) by the Lithuanian Science Council under Project No. MIP-79/2010. ; |
Approved |
Most recent IF: 2.925; 2012 IF: 3.042 |
|
| |
Call Number |
UA @ lucian @ c:irua:100822 |
Serial |
2948 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Sena, S.H.R.; Pereira, J.M.; Farias, G.A.; Peeters, F.M. |
|
| |
Title |
Cyclotron resonance of trilayer graphene |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
86 |
Issue |
8 |
Pages |
085412 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The cyclotron resonance energies, the corresponding oscillator strengths, and the cyclotron absorption spectrum for trilayer graphene are calculated for both ABA and ABC stacking. A gate potential across the stacked layers leads to (1) a reduction of the transition energies, (2) a lifting of the degeneracy of the zero Landau level, and (3) the removal of the electron-hole symmetry. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000307273100009 |
Publication Date |
2012-08-08 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
|
|
| |
Notes |
; This work was supported by the National Council for the Improvement of Higher education (CAPES), the Brazilian Council for Research (CNPq), the Flemish Science Foundation (FWO-V1), the bilateral projects between Flanders and Brazil and the CNPq and FWO-V1, and the ESF-Eurographene project CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:100815 |
Serial |
604 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Xiao, Y.M.; Xu, W.; Zhang, Y.Y.; Peeters, F.M. |
|
| |
Title |
Optoelectronic properties of ABC-stacked trilayer graphene |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
|
| |
Volume |
250 |
Issue |
1 |
Pages |
86-94 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We present a theoretical study on the optoelectronic properties of ABC-stacked trilayer graphene (TLG). The optical conductance and light transmittance are evaluated through using the energy-balance equation derived from the Boltzmann equation for an air/graphene/dielectric-wafer system in the presence of linearly polarized radiation field. The results obtained from two band structure models are examined and compared. For short wavelength radiation, the universal optical conductance sigma(0) = 3e(2)/(4h) can be obtained. Importantly, there exists an optical absorption window in the radiation wavelength range 10-200 mu m, which is induced by different transition energies required for inter- and intra-band optical absorption channels. As a result, we find that the position and width of this window depend sensitively on temperature and carrier density of the system, especially the lower frequency edge. There is a small characteristic absorption peak at about 82 mu m where the largest interband transition states exist in the ABC-stacked TLG model, in contrast to the relatively smooth curves in a simplified model. These theoretical results indicate that TLG has some interesting and important physical properties which can be utilized to realize infrared or THz optoelectronic devices. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Berlin |
Editor |
|
|
| |
Language |
|
Wos |
000313347500011 |
Publication Date |
2012-08-08 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.674 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
; This work was supported by the National Natural Science Foundation of China (grant no. 10974206), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. One of us (F.M.P.) was a Specially Appointed Foreign Professor of the Chinese Academy of Sciences. ; |
Approved |
Most recent IF: 1.674; 2013 IF: 1.605 |
|
| |
Call Number |
UA @ lucian @ c:irua:110109 |
Serial |
2495 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Saniz, R.; Xu, Y.; Matsubara, M.; Amini, M.N.; Dixit, H.; Lamoen, D.; Partoens, B. |
|
| |
Title |
A simplified approach to the band gap correction of defect formation energies : Al, Ga, and In-doped ZnO |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
The journal of physics and chemistry of solids |
Abbreviated Journal |
J Phys Chem Solids |
|
| |
Volume |
74 |
Issue |
1 |
Pages |
45-50 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
The calculation of defect levels in semiconductors within a density functional theory approach suffers greatly from the band gap problem. We propose a band gap correction scheme that is based on the separation of energy differences in electron addition and relaxation energies. We show that it can predict defect levels with a reasonable accuracy, particularly in the case of defects with conduction band character, and yet is simple and computationally economical. We apply this method to ZnO doped with group III elements (Al, Ga, In). As expected from experiment, the results indicate that Zn substitutional doping is preferred over interstitial doping in Al, Ga, and In-doped ZnO, under both zinc-rich and oxygen-rich conditions. Further, all three dopants act as shallow donors, with the +1 charge state having the most advantageous formation energy. Also, doping effects on the electronic structure of ZnO are sufficiently mild so as to affect little the fundamental band gap and lowest conduction bands dispersion, which secures their n-type transparent conducting behavior. A comparison with the extrapolation method based on LDA+U calculations and with the HeydScuseriaErnzerhof hybrid functional (HSE) shows the reliability of the proposed scheme in predicting the thermodynamic transition levels in shallow donor systems. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
|
| |
Language |
|
Wos |
000311062500009 |
Publication Date |
2012-08-10 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0022-3697; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.059 |
Times cited |
36 |
Open Access |
|
|
| |
Notes |
Fwo; Bof-Nio |
Approved |
Most recent IF: 2.059; 2013 IF: 1.594 |
|
| |
Call Number |
UA @ lucian @ c:irua:101782 |
Serial |
3004 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Sena, S.H.R.; Pereira, J.M.; Farias, G.A.; Peeters, F.M.; Costa Filho, R.N. |
|
| |
Title |
The electronic properties of graphene and graphene ribbons under simple shear strain |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
|
| |
Volume |
24 |
Issue |
37 |
Pages |
375301 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
A tight-binding model is used to study the energy band of graphene and graphene ribbon under simple shear strain. The ribbon consists of lines of carbon atoms in an armchair or zigzag orientation where a simple shear strain is applied in the x-direction keeping the atomic distances in the y-direction unchanged. Such modification in the lattice gives an energy band that differs in several aspects from the one without any shear and with pure shear. The changes in the spectrum depend on the line displacement of the ribbon, and also on the modified hopping parameter. It is also shown that this simple shear strain tunes the electronic properties of both graphene and graphene ribbon, opening and closing energy gaps for different displacements of the system. The modified density of states is also shown. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
000308202700011 |
Publication Date |
2012-08-14 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.649 |
Times cited |
15 |
Open Access |
|
|
| |
Notes |
; This work was supported by CNPq (RNCF), the National Council for the Improvement of Higher Education (CAPES), the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the bilateral program between Flanders and Brazil. ; |
Approved |
Most recent IF: 2.649; 2012 IF: 2.355 |
|
| |
Call Number |
UA @ lucian @ c:irua:101838 |
Serial |
1000 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Sivek, J.; Leenaerts, O.; Partoens, B.; Peeters, F.M. |
|
| |
Title |
First-principles investigation of bilayer fluorographene |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
|
| |
Volume |
116 |
Issue |
36 |
Pages |
19240-19245 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Ab initio calculations within the density functional theory formalism are performed to investigate the stability and electronic properties of fluorinated bilayer graphene (bilayer fluorographene). A comparison is made to previously investigated graphane, bilayer graphane, and fluorographene. Bilayer fluorographene is found to be a much more stable material than bilayer graphane. Its electronic band structure is similar to that of monolayer fluorographene, but its electronic band gap is significantly larger (about 1 eV). We also calculate the effective masses around the Gamma-point for fluorographene and bilayer fluorographene and find that they are isotropic, in contrast to earlier reports. Furthermore, it is found that bilayer fluorographene is almost as strong as graphene, as its 2D Young's modulus is approximately 300 N m(-1). |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
|
| |
Language |
|
Wos |
000308631300022 |
Publication Date |
2012-08-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.536 |
Times cited |
39 |
Open Access |
|
|
| |
Notes |
; This work is supported by the ESF-Eurocores program EuroGRAPHENE (project CONERAN) and the Flemish Science Foundation (FWO-V1). ; |
Approved |
Most recent IF: 4.536; 2012 IF: 4.814 |
|
| |
Call Number |
UA @ lucian @ c:irua:101842 |
Serial |
1211 |
|
| Permanent link to this record |
