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Author |
Jain, R.; Rather, J.A.; Dwivedi, A. |
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Title |
Voltammetric behaviour of nitroxazepine in solubilized system and biological fluids |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Materials science and engineering: part C: biomimetic materials |
Abbreviated Journal |
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Volume |
31 |
Issue |
2 |
Pages |
230-237 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
This study reports the development and validation of sensitive and selective assay method for the determination of the antidepressant drug in solubilized system and biological fluids. Solubilized system of different surfactants including cationic, anionic and non-ionic influences the electrochemical response of drug. Addition of cationic surfactant cetrimide to the solution containing drug enhances the peak current signal while anionic and non-ionic showed an opposite effect. The current signal due to reduction process was function of concentration of nitroxazepine, pH, type of surfactant and preconcentration time at the electrode surface. The reduction process is irreversible and adsorption controlled at HMDE. Various chemical and instrumental parameters affecting the monitored electroanalytical response were investigated and optimized for niroxazepine hydrochloride determination. The proposed SWCAdSV and DPCAdSV methods are linear over the concentration range 2.0 × 10-7 5.0 × 10-9 mol/L and 6.1 × 10-7 1.0 × 10-8 mol/L with detection limit of 1.62 × 10-10 mo/L and 1.4 × 10-9 mo/L respectively. The method shows good sensitivity, selectivity, accuracy and precision that makes it very suitable for determination of nitroxazepine in pharmaceutical formulation and biological fluids. |
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Wos |
000286707900024 |
Publication Date |
2010-09-08 |
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Edition |
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ISSN |
0928-4931 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:98685 |
Serial |
8743 |
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Author |
Jain, R.; Rather, J.A. |
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Title |
Voltammetric determination of antibacterial drug gemifloxacin in solubilized systems at multi-walled carbon nanotubes modified glassy carbon electrode |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Colloids and surfaces: B : biointerfaces |
Abbreviated Journal |
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Volume |
83 |
Issue |
2 |
Pages |
340-346 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
A sensitive electroanalytical method for determination of gemifloxacin in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at multi-walled carbon nanotubes modified glassy carbon electrode in the presence of CTAB. Solubilized system of different surfactants including SDS, Tween-20 and CTAB were taken for the study of electrochemical behaviour of gemifloxacin at modified electrode. The reduction peak current increases in the presence of CTAB while other surfactants show opposite effect. The modified electrode exhibits catalytic activity, high sensitivity, stability and is applicable over wide range of concentration for the determination of gemifloxacin. The mechanism of electrochemical reduction of gemifloxacin has been proposed on the basis of CV, SWV, DPV and coulometeric techniques. The proposed squarewave voltammetric method shows linearity over the concentration range 2.4715.5 μg/mL. The achieved limits of detection (LOD) and quantification (LOQ) are 0.90 ng/mL and 3.0 ng/mL respectively. |
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Wos |
000287268000020 |
Publication Date |
2010-12-08 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0927-7765 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:98687 |
Serial |
8744 |
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Author |
Worobiec, A.; Potgieter-Vermaak, S.S.; Berghmans, P.; Winkler, H.; Burger, R.; Van Grieken, R. |
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Title |
Air particulate emissions in developing countries : a case study in South Africa |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Analytical letters |
Abbreviated Journal |
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Volume |
44 |
Issue |
11 |
Pages |
1907-1924 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
Atmospheric aerosols were collected during the winter in Bethlehem, South Africa. The particulate mass concentrations, ambient carbon mass concentrations, and chemical composition of various particulate fractions showed that the area is highly polluted. The fine particle mass concentrations peaked at 1000 µg/m3 for PM2.5. Ambient carbon mass concentrations ranged from 20 to 40 µg/m3. Single particle analysis confirmed that the fine particle fraction was dominated by organic particles. The topographical conditions, causing a low inversion, together with the high amounts of emissions from biomass burning, result in unacceptable levels of air pollution and pose a considerable health threat to the population. |
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Wos |
000294602300006 |
Publication Date |
2011-08-12 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2719 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:91079 |
Serial |
7429 |
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Permanent link to this record |
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Author |
Darchuk, L.; Gatto Rotondo, G.; Swaenen, M.; Worobiec, A.; Tsybrii, Z.; Makarovska, Y.; Van Grieken, R. |
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Title |
Composition of prehistoric rock-painting pigments from Egypt (Gilf Kébir area) |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Spectrochimica acta: part A: molecular and biomolecular spectroscopy |
Abbreviated Journal |
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Volume |
83 |
Issue |
1 |
Pages |
34-38 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
The composition of rock-painting pigments from Egypt (Gilf Kebia area) has been analyzed by means of molecular spectroscopy such as Fourier transform infrared and micro-Raman spectroscopy and scanning electron microscopy coupled to an energy dispersive X-ray spectrometer and X-ray fluorescence analysis. Red and yellow pigments were recognized as red and yellow ochre with additional rutile. |
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Wos |
000296827600005 |
Publication Date |
2011-07-26 |
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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 |
1386-1425 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:92015 |
Serial |
7713 |
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Permanent link to this record |
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Author |
Worobiec, A.; Darchuk, L.; Brooker, A.; Potgieter, H.; Van Grieken, R. |
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Title |
Damage and molecular changes under a laser beam in SEM-EDX/MRS interface : a case study on iron-rich particles |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of Raman spectroscopy |
Abbreviated Journal |
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Volume |
42 |
Issue |
4 |
Pages |
808-814 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
The control of damage to individual environmental particles by a laser beam during Raman spectroscopy carried out in ambient air is generally well understood. The nature and control of damage under vacuum conditions (e.g. in the scanning electron microscopy with energy X-ray detection combined with micro-Raman spectroscopyinterfaced SEM-EDX/MRS) are more complex and less well comprehended. The physical and chemical processes that affect the damage caused to small particles by lasers still remain somewhat unclear, but certainly the atmosphere (vacuum/air) and the beam intensity have very significant influences. Furthermore, it has been determined that some particles (e.g. haematite), although stable under an electron beam, are damaged by the laser beam, hampering their analysis. Additionally, when simultaneous analyses by SEM/EDX and MRS are considered, the correct choice of the collection surface plays a crucial role. As a result, the following collection substrates were tested to determine their influence on the laser beam damage process to the particle: silver and aluminium foils and silicon wafers. A test study was performed using artificial examples of haematite (Fe2O3) particles. Exposure of Fe2O3 particles in vacuum to 514- and 785-nm laser radiation often leads to their melting, transformation and evaporation. The dependence of the damage caused by the laser beam on the particle structure is reported here. Molecular and crystallographic changes have also been revealed. Formation of magnetite (as an effect of re-crystallisation) and Raman inactive structures was detected. |
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Wos |
000290484700033 |
Publication Date |
2010-09-27 |
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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 |
0377-0486 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:89518 |
Serial |
7751 |
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Permanent link to this record |
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Author |
Darchuk, L.A.; Zaverbna, L.V.; Worobiec, A.; Van Grieken, R. |
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Title |
Structural features of human tooth tissues affected by high dose of external ionizing radiation after nuclear catastrophe of Chernobyl plant |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Microchemical journal |
Abbreviated Journal |
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Volume |
97 |
Issue |
2 |
Pages |
282-285 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
The application of micro-Raman spectroscopy is discussed for the analysis of structural features of human tooth tissues affected by high doses of external ionizing radiation (0.51.7 Gy) after the nuclear plant catastrophe in Chernobyl in 1986. The results have shown significant changes in the mineral matrix of dental enamel that lead to the decrease of tooth enamel hardness. Destruction of the collagen chain of the organic matrix has been observed for dentin and cementum. |
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Wos |
000286558200029 |
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 |
0026-265x; 0026-265x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:86818 |
Serial |
8585 |
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Permanent link to this record |
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Author |
Van Grieken, R.; Worobiec, A. |
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Title |
X-ray spectrometry for preventive conservation of cultural heritage |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Pramåna: a journal of physics |
Abbreviated Journal |
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Volume |
72 |
Issue |
2 |
Pages |
191-200 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
Analytical chemistry does play a key role in the chemical characterization of the environment and it appears that X-ray spectrometry, in its many forms, is one of the most relevant analytical techniques in preventive conservation, as it is in cultural heritage research in general. X-ray spectrometry has indeed been the method of choice for the characterization of the inorganic composition of atmospheric aerosols, for a long time. We have, over the last decade, intensively used various forms of X-ray spectrometry, viz., mostly energy-dispersive X-ray fluorescence, e.g. with polarized high-energy beam excitation, and automated electron probe X-ray microanalysis, together with other techniques, to identify particle types and their sources in indoor environments, including museums, while gaseous indoor pollutants were assessed using passive diffusion samplers. In each case, both bulk aerosols and individual aerosol particles were studied. For microanalysis of single particles, we have investigated a dozen techniques, but for wide, real-life applications, automated electron probe X-ray microanalysis is the most rewarding. We have first studied atmospheric aerosols in and around the Correr Museum in Venice, many other museums in Austria, Japan and England, and in the caves with prehistoric rock paintings in Altamira, Spain. Very recently, measurements were done in the Metropolitan Museum of Art in New York and theWawel Castle in Cracow, in Italian and Polish mountain churches, in a number of museums in Belgium and the Netherlands, and in cathedrals with medieval stained glass windows. In the Correr museum, it appeared that the particles most threatening for the Bellini paintings were released by the deteriorating plaster renderings, and this could be avoided by simply improving the rendering on the museum walls. In the Wawel Castle, outdoor pollution particles, like fine soot from diesel traffic, entering via leaks in the windows and doors, and also street-deicing salts and coal burning pollution particles, brought in by visitors, mostly in winter, were found to be most worrisome. Urgent questions that are not solved at this moment pertain to the deposition processes from the atmosphere to the cultural heritage items, the critical surface interactions that take place on these items, and the establishment of suitable particle concentration standards. |
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Wos |
000288861000002 |
Publication Date |
2011-05-20 |
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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 |
0304-4289; 0973-7111 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:87025 |
Serial |
8785 |
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Permanent link to this record |
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Author |
Karapetrov, G.; Belkin, A.; Iavarone, M.; Fedor, J.; Novosad, V.; Milošević, M.V.; Peeters, F.M. |
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Title |
Anisotropic superconductivity and vortex dynamics in magnetically coupled F/S and F/S/F hybrids |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of superconductivity and novel magnetism |
Abbreviated Journal |
J Supercond Nov Magn |
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Volume |
24 |
Issue |
1/2 |
Pages |
905-910 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Magnetically coupled superconductorferromagnet hybrids offer advanced routes for nanoscale control of superconductivity. Magnetotransport characteristics and scanning tunneling microscopy images of vortex structures in superconductorferromagnet hybrids reveal rich superconducting phase diagrams. Focusing on a particular combination of a ferromagnet with a well-ordered periodic magnetic domain structure with alternating out-of-plane component of magnetization, and a small coherence length superconductor, we find directed nucleation of superconductivity above the domain wall boundaries. We show that near the superconductor-normal state phase boundary the superconductivity is localized in narrow mesoscopic channels. In order to explore the Abrikosov flux line ordering in F/S hybrids, we use a combination of scanning tunneling microscopy and GinzburgLandau simulations. The magnetic stripe domain structure induces periodic local magnetic induction in the superconductor, creating a series of pinninganti-pinning channels for externally added magnetic flux quanta. Such laterally confined Abrikosov vortices form quasi-1D arrays (chains). The transitions between multichain states occur through propagation of kinks at the intermediate fields. At high fields we show that the system becomes nonlinear due to a change in both the number of vortices and the confining potential. In F/S/F hybrids we demonstrate the evolution of the anisotropic conductivity in the superconductor that is magnetically coupled with two adjacent ferromagnetic layers. Stripe magnetic domain structures in both F-layers are aligned under each other, resulting in a directional superconducting order parameter in the superconducting layer. The conductance anisotropy strongly depends on the period of the magnetic domains and the strength of the local magnetization. The anisotropic conductivity of up to three orders of magnitude can be achieved with a spatial critical temperature modulation of 5% of T c. Induced anisotropic properties in the F/S and F/S/F hybrids have a potential for future application in switching and nonvolatile memory elements operating at low temperatures. |
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Corporate Author |
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Publisher |
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Place of Publication |
New York, N.Y. |
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Language |
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Wos |
000289855700150 |
Publication Date |
2010-10-01 |
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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 |
1557-1939;1557-1947; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.18 |
Times cited |
2 |
Open Access |
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Notes |
; This work as well as the use of the Center for Nanoscale Materials and the Electron Microscopy Center at Argonne National Laboratory were supported by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. This work was also supported by the Ministry of Education, Agency for Structural Funds of the European Union, Research and Development Program, under agreement 262 401 200 19. M.V.M. and F. M. P. acknowledge support from the Flemish Science Foundation (FWO-VI), the Belgian Science Policy, the JSPS/ESF-NES program, the ESF-AQDJJ network, and the Vlaanderen-USA bilateral program. ; |
Approved |
Most recent IF: 1.18; 2011 IF: 0.650 |
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Call Number |
UA @ lucian @ c:irua:89930 |
Serial |
130 |
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Permanent link to this record |
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Author |
Matulis, A.; Masir, M.R.; Peeters, F.M. |
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Title |
Application of optical beams to electrons in graphene |
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 |
11 |
Pages |
115458-115458,7 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The technique of beam optics is applied to the description of the wave function of Dirac electrons. This approach is illustrated by considering electron transmission through simple nonhomogeneous structures, such as flat and bent p-n junctions and superlattices. We found that a convex p-n junction compresses the beam waist, while a concave interface widens it without loosing its focusing properties. At a flat p-n junction the waist of the transmitted Gaussian beam can be narrowed or widened, depending on the angle of incidence. A general condition is derived for the occurrence of beam collimation in a superlattice which is less stringent than previous discussed. |
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Place of Publication |
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Language |
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Wos |
000288896400013 |
Publication Date |
2011-03-29 |
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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 |
13 |
Open Access |
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Notes |
; This research was supported by the Flemish Science Foundation (Grant No. FWO-Vl), by the Belgian Science policy (IAP), and (in part) by the Lithuanian Science Council under project No. MIP-79/2010. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:89377 |
Serial |
142 |
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Permanent link to this record |
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Author |
Apolinario, S.W.S.; Peeters, F.M. |
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Title |
Binary dusty plasma Coulomb balls |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics |
Abbreviated Journal |
Phys Rev E |
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Volume |
83 |
Issue |
4 |
Pages |
041136,1-041136,8 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigated the mixing and segregation of a system consisting of two different species of particles, having different charges, interacting through a pure Coulomb potential, and confined in a three-dimensional parabolic trap. The structure of the cluster and its normal mode spectrum are analyzed as a function of the relative charge and the relative number of different types of particles. We found that (a) the system can be in a mixed or segregated state depending on the relative charge ratio parameter and (b) the segregation process is mediated by a first or second order structural phase transition which strongly influences the magic cluster properties of the system. |
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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 |
000290154900004 |
Publication Date |
2011-04-29 |
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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 |
1539-3755;1550-2376; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.366 |
Times cited |
10 |
Open Access |
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Notes |
; This work was supported by FACEPE (Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco) and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 2.366; 2011 IF: 2.255 |
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Call Number |
UA @ lucian @ c:irua:89716 |
Serial |
236 |
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Permanent link to this record |
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Author |
Neek-Amal, M.; Peeters, F.M. |
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Title |
Buckled circular monolayer graphene : a graphene nano-bowl |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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Volume |
23 |
Issue |
4 |
Pages |
045002-045002,8 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate the stability of circular monolayer graphene subjected to a radial load using non-equilibrium molecular dynamics simulations. When monolayer graphene is radially stressed, after some small circular strain (~0.4%) it buckles and bends into a new bowl-like shape. Young's modulus is calculated from the linear relation between stress and strain before the buckling threshold, which is in agreement with experimental results. The prediction of elasticity theory for the buckling threshold of a radially stressed plate is presented and its results are compared to the one of our atomistic simulation. The Jarzynski equality is used to estimate the difference between the free energy of the non-compressed states and the buckled states. From a calculation of the free energy we obtain the optimum radius for which the system feels the minimum boundary stress. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
London |
Editor |
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Language |
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Wos |
000286142800003 |
Publication Date |
2010-12-16 |
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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 |
0953-8984;1361-648X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.649 |
Times cited |
27 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). ; |
Approved |
Most recent IF: 2.649; 2011 IF: 2.546 |
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Call Number |
UA @ lucian @ c:irua:88043 |
Serial |
259 |
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Permanent link to this record |
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Author |
Zarenia, M.; Pereira, J.M.; Farias, G.A.; Peeters, F.M. |
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Title |
Chiral states in bilayer graphene : magnetic field dependence and gap opening |
Type |
A1 Journal article |
|
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
84 |
Issue |
12 |
Pages |
125451-125451,13 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
At the interface of electrostatic potential kink profiles, one-dimensional chiral states are found in bilayer graphene (BLG). Such structures can be created by applying an asymmetric potential to the upper and the lower layers of BLG. We found the following: (i) due to the strong confinement by the single kink profile, the unidirectional states are only weakly affected by a magnetic field; (ii) increasing the smoothness of the kink potential results in additional bound states, which are topologically different from those chiral states; and (iii) in the presence of a kink-antikink potential, the overlap between the oppositely moving chiral states results in the appearance of crossing and anticrossing points in the energy spectrum. This leads to the opening of tunable minigaps in the spectrum of the unidirectional topological states. |
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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 |
000295484300016 |
Publication Date |
2011-09-30 |
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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 |
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 |
; This work was supported by the Flemish Science Foundation (FWO-VI), the Belgian Science Policy (IAP), the European Science Foundation (ESF) under the EUROCORES program EuroGRAPHENE (project CONGRAN), the Brazilian agency CNPq (Pronex), and the bilateral projects between Flanders and Brazil and the collaboration project FWO-CNPq. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:92915 |
Serial |
358 |
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Permanent link to this record |
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Author |
Chaves, A.; Komendová, L.; Milošević, M.V.; Andrade, J.S.; Farias, G.A.; Peeters, F.M. |
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Title |
Conditions for nonmonotonic vortex interaction in two-band 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 |
21 |
Pages |
214523-214523,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We describe a semianalytic approach to the two-band Ginzburg-Landau theory, which predicts the behavior of vortices in two-band superconductors. We show that the character of the short-range vortex-vortex interaction is determined by the sign of the normal domain-superconductor interface energy, in analogy with the conventional differentiation between type I and type II superconductors. However, we also show that the long-range interaction is determined by a modified Ginzburg-Landau parameter κ*, different from the standard κ of a bulk superconductor. This opens the possibility for nonmonotonic vortex-vortex interaction, which is temperature dependent, and can be further tuned by alterations of the material on the microscopic scale. |
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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 |
000292252300009 |
Publication Date |
2011-06-30 |
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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 |
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 |
46 |
Open Access |
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Notes |
; Discussions with A. Moreira, A. Shanenko, R. Prozorov, and A. Golubov are gratefully acknowledged. This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the bilateral project FWO-CNPq, CAPES, and PRONEX/CNPq/FUNCAP. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:90922 |
Serial |
477 |
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Permanent link to this record |
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Author |
Peelaers, H.; Partoens, B.; Giantomassi, M.; Rangel, T.; Goossens, E.; Rignanese, G.-M.; Gonze, X.; Peeters, F.M. |
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Title |
Convergence of quasiparticle band structures of Si and Ge nanowires in the GW approximation and the validity of scissor shifts |
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 |
4 |
Pages |
045306-045306,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Starting from fully converged density-functional theory calculations, the quasiparticle corrections are calculated for different sized Si and Ge nanowires using the GW approximation. The effectiveness of recently developed techniques in speeding up the convergence of the quasiparticle calculations is demonstrated. The complete quasiparticle band structures are also obtained using an interpolation technique based on maximallylocalized Wannier functions. From the quasiparticle results, we assess the correctness of the commonly applied scissor-shift correction. Dispersion changes are observed, which are also reflected in changes in the effective band masses calculated taking into account quasiparticle corrections. |
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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 |
000286771400004 |
Publication Date |
2011-01-21 |
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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 |
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 |
; We are grateful to Yann Pouillon for valuable technical support with the build system of ABINIT, related to the WANNIER90 library. This work was supported by the Flemish Science Foundation (FWO-Vl) and by the Interuniversity Attraction Poles Program (P6/42)-Belgian State-Belgian Science Policy. X. G. and G.-M. R. acknowledge funding from the EU's 7th Framework Programme through the ETSF I3 e-Infrastructure project (Grant No. 211956), the Communaute francaise de Belgique through the Action de Recherche Concertee 07/12-003 “Nanosystemes hybrides metal-organiques,” and the Wallon Region Project No. 816849 “ European Theoretical Spectroscopy Facility” (WALL ETSF). M. G. acknowledges funding from the FRFC Project No. 2.4.589.09.F. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:86905 |
Serial |
510 |
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Permanent link to this record |
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Author |
Komendová, L.; Milošević, M.V.; Shanenko, A.A.; Peeters, F.M. |
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Title |
Different length scales for order parameters in two-gap superconductors : extended Ginzburg-Landau theory |
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 |
84 |
Issue |
6 |
Pages |
064522-064522,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using the Ginzburg-Landau theory extended to the next-to-leading order, we determine numerically the healing lengths of the two order parameters at the two-gap superconductor/normal metal interface. We demonstrate on several examples that those can be different even in the strict domain of applicability of the Ginzburg-Landau theory. This justifies the use of this theory to describe relevant physics of two-gap superconductors, distinguishing them from their single-gap counterparts. The calculational degree of complexity increases only slightly with respect to the conventional Ginzburg-Landau expansion, thus the extended Ginzburg-Landau model remains numerically far less demanding compared to the full microscopic approaches. |
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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 |
000294226000013 |
Publication Date |
2011-08-25 |
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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 |
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 |
56 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF-INSTANS network. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:92414 |
Serial |
695 |
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Permanent link to this record |
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Author |
Tkachenko, D.V.; Sheridan, T.E.; Misko, V.R. |
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Title |
Dispersion relations for circular single and double dusty plasma chains |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physics of plasmas |
Abbreviated Journal |
Phys Plasmas |
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Volume |
18 |
Issue |
10 |
Pages |
103709,1-103709,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We derive dispersion relations for a system of identical particles confined in a two-dimensional annular harmonic well and which interact through a Yukawa potential, e.g., a dusty plasma ring. When the particles are in a single chain (i.e., a one-dimensional ring), we find a longitudinal acoustic mode and a transverse optical mode which show approximate agreement with the dispersion relation for a straight configuration for large radii of the ring. When the radius decreases, the dispersion relations modify: there appears an anticrossing of the modes near the crossing point resulting in a frequency gap between the lower and upper branches of the modified dispersion relations. For the double chain (i.e., a two-dimensional zigzag configuration), the dispersion relation has four branches: longitudinal acoustic and optical and transverse acoustic and optical. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Woodbury, N.Y. |
Editor |
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Language |
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Wos |
000296529600090 |
Publication Date |
2011-10-21 |
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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 |
1070-664X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.115 |
Times cited |
7 |
Open Access |
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Notes |
; We acknowledge fruitful discussions with F.M. Peeters, A. Matulis, and W.P. Ferreira. This work was supported by the “Odysseus” program of the Flemish Government and FWO-Vl. ; |
Approved |
Most recent IF: 2.115; 2011 IF: 2.147 |
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Call Number |
UA @ lucian @ c:irua:94052 |
Serial |
738 |
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Permanent link to this record |
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Author |
Khaydarov, R.T.; Beisinbaeva, H.B.; Sabitov, M.M.; Kalal, M.; Berdiyorov, G.R. |
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Title |
Effect of light gas atom inclusions on the characteristics of laser-produced plasma ions |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Nuclear fusion |
Abbreviated Journal |
Nucl Fusion |
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Volume |
51 |
Issue |
10 |
Pages |
103041,1-103041,3 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using the mass-spectrometric method we studied the effect of light gas inclusions on the formation process of multi-component laser-induced plasma ions. Masscharge characteristics, as well as energy and spatial distribution of the plasma ions are analysed. We found that both the energy and maximal charge of heavy component ions decrease due to the presence of gas atoms in the solid target surface layer. |
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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 |
Vienna |
Editor |
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Language |
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Wos |
000296603800043 |
Publication Date |
2011-09-23 |
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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 |
0029-5515;1741-4326; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.307 |
Times cited |
1 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.307; 2011 IF: 4.090 |
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Call Number |
UA @ lucian @ c:irua:93761 |
Serial |
821 |
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Permanent link to this record |
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Author |
Sofo, J.O.; Suarez, A.M.; Usaj, G.; Cornaglia, P.S.; Hernández-Nieves, A.D.; Balseiro, C.A. |
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Title |
Electrical control of the chemical bonding of fluorine on graphene |
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 |
8 |
Pages |
081411 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We study the electronic structure of diluted F atoms chemisorbed on graphene using density functional theory calculations. We show that the nature of the chemical bonding of a F atom adsorbed on top of a C atom in graphene strongly depends on carrier doping. In neutral samples the F impurities induce a sp(3)-like bonding of the C atom below, generating a local distortion of the hexagonal lattice. As the graphene is electron-doped, the C atom retracts back to the graphene plane and for high doping (10(14) cm(-2)) its electronic structure corresponds to a nearly pure sp(2) configuration. We interpret this sp(3)-sp(2) doping-induced crossover in terms of a simple tight-binding model and discuss the physical consequences of this change. |
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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 |
000287484800005 |
Publication Date |
2011-02-18 |
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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 |
65 |
Open Access |
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Notes |
; J.O.S. and A. S. acknowledge support from the Donors of the American Chemical Society Petroleum Research Fund and use of facilities at the Penn State Materials Simulation Center. G. U., P. S. C., A. D. H., and C. A. B. acknowledge financial support from PICTs 06-483 and 2008-2236 from ANPCyT and PIP 11220080101821 from CONICET, Argentina. A. D. H. acknowledges support from the Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:105600 |
Serial |
892 |
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Permanent link to this record |
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Author |
Grujić, M.; Zarenia, M.; Chaves, A.; Tadić, M.; Farias, G.A.; Peeters, F.M. |
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Title |
Electronic and optical properties of a circular graphene quantum dot in a magnetic field : influence of the boundary conditions |
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 |
84 |
Issue |
20 |
Pages |
205441-205441,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
An analytical approach, using the Dirac-Weyl equation, is implemented to obtain the energy spectrum and optical absorption of a circular graphene quantum dot in the presence of an external magnetic field. Results are obtained for the infinite-massand zigzag boundary conditions. We found that the energy spectrum of a dot with the zigzag boundary condition exhibits a zero-energy band regardless of the value of the magnetic field, while for the infinite-mass boundary condition, the zero-energy states appear only for high magnetic fields. The analytical results are compared to those obtained from the tight-binding model: (i) we show the validity range of the continuum model and (ii) we find that the continuum model with the infinite-mass boundary condition describes rather well its tight-binding analog, which can be partially attributed to the blurring of the mixed edges by the staggered potential. |
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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 |
000297295400011 |
Publication Date |
2011-11-21 |
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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 |
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 |
78 |
Open Access |
|
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|
Notes |
; This work was supported by the EuroGraphene programme of the ESF (project CONGRAN), the Ministry of Education and Science of Serbia, the Belgian Science Policy (IAP), the bilateral projects between Flanders and Brazil, the Flemish Science Foundation (FWO-Vl), and the Brazilian Research Council (CNPq). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:94025 |
Serial |
997 |
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Permanent link to this record |
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Author |
Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
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Title |
Energy levels of triangular and hexagonal graphene quantum dots : a comparative study between the tight-binding and Dirac equation approach |
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 |
84 |
Issue |
24 |
Pages |
245403-245403,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The Dirac equation is solved for triangular and hexagonal graphene quantum dots for different boundary conditions in the presence of a perpendicular magnetic field. We analyze the influence of the dot size and its geometry on their energy spectrum. A comparison between the results obtained for graphene dots with zigzag and armchair edges, as well as for infinite-mass boundary condition, is presented and our results show that the type of graphene dot edge and the choice of the appropriate boundary conditions have a very important influence on the energy spectrum. The single-particle energy levels are calculated as a function of an external perpendicular magnetic field that lifts degeneracies. Comparing the energy spectra obtained from the tight-binding approximation to those obtained from the continuum Dirac equation approach, we verify that the behavior of the energies as a function of the dot size or the applied magnetic field are qualitatively similar, but in some cases quantitative differences can exist. |
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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 |
000297767800008 |
Publication Date |
2011-12-07 |
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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 |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.836 |
Times cited |
145 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE (project CONGRAN), the Bilateral program between Flanders and Brazil, CAPES and the Brazilian Council for Research (CNPq). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93961 |
Serial |
1040 |
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Permanent link to this record |
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Author |
Saniz, R.; Barbiellini, B.; Denison, A.B.; Bansil, A. |
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Title |
Erratum: Spontaneous magnetization and electron momentum density in three-dimensional quantum dots [Phys. Rev. B 68, 165326 (2003)] |
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 |
84 |
Issue |
11 |
Pages |
119907 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
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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 |
000295263600015 |
Publication Date |
2011-09-28 |
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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 |
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Impact Factor |
3.836 |
Times cited |
|
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:92919 |
Serial |
1081 |
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Permanent link to this record |
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Author |
Tadić, M.; Čukarić, N.; Arsoski, V.; Peeters, F.M. |
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Title |
Excitonic Aharonov-Bohm effect : unstrained versus strained type-I semiconductor nanorings |
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 |
84 |
Issue |
12 |
Pages |
125307-125307,13 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We study how mechanical strain affects the magnetic field dependence of the exciton states in type-I semiconductor nanorings. Strain spatially separates the electron and hole in (In,Ga)As/GaAs nanorings which is beneficial for the occurrence of the excitonic Aharonov-Bohm (AB) effect. In narrow strained (In,Ga)As/GaAs nanorings the AB oscillations in the exciton ground-state energy are due to anticrossings with the first excited state. No such AB oscillations are found in unstrained GaAs/(Al,Ga)As nanorings irrespective of the ring width. Our results are obtained within an exact numerical diagonalization scheme and are shown to be accurately described by a two-level model with off-diagonal coupling t. The later transfer integral expresses the Coulomb coupling between states of electron-hole pairs. We also found that the oscillator strength for exciton recombination in (In,Ga)As/GaAs nanorings exhibits AB oscillations, which are superimposed on a linear increase with magnetic field. Our results agree qualitatively with recent experiments on the excitonic Aharonov-Bohm effect in type-I (In,Ga)As/GaAs nanorings. |
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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 |
000294777400013 |
Publication Date |
2011-09-09 |
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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 |
13 |
Open Access |
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Notes |
; This work was supported by the Ministry of Education and Science of Serbia, the Flemish Science Foundation (FWO-Vl), the EU NoE: SANDiE, and the Belgian Science Policy (IAP). The calculations were performed on the CalcUA and Seastar computer clusters of the University of Antwerp. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:92326 |
Serial |
1122 |
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Permanent link to this record |
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Author |
Shanenko, A.A.; Milošević, M.V.; Peeters, F.M. |
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Title |
Extended Ginzburg-Landau formalism for two-band superconductors |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
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Volume |
106 |
Issue |
4 |
Pages |
047005-047005,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Recent observation of unusual vortex patterns in MgB2 single crystals raised speculations about possible type-1.5 superconductivity in two-band materials, mixing the properties of both type-I and type-II superconductors. However, the strict application of the standard two-band Ginzburg-Landau (GL) theory results in simply proportional order parameters of the two bandsand does not support the type-1.5 behavior. Here we derive the extended GL formalism (accounting all terms of the next order over the small τ=1-T/Tc parameter) for a two-band clean s-wave superconductor and show that the two condensates generally have different spatial scales, with the difference disappearing only in the limit T→Tc. The extended version of the two-band GL formalism improves the validity of GL theory below Tc and suggests revisiting the earlier calculations based on the standard model. |
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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 |
New York, N.Y. |
Editor |
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Language |
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Wos |
000286734100010 |
Publication Date |
2011-01-27 |
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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 |
0031-9007;1079-7114; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.462 |
Times cited |
84 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF-INSTANS network. Discussions with M. D. Croitoru are gratefully acknowledged. ; |
Approved |
Most recent IF: 8.462; 2011 IF: 7.370 |
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Call Number |
UA @ lucian @ c:irua:88038 |
Serial |
1154 |
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Permanent link to this record |
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Author |
Nowak, M.P.; Szafran, B.; Peeters, F.M. |
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Title |
Fano resonances and electron spin transport through a two-dimensional spin-orbit-coupled quantum ring |
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 |
84 |
Issue |
23 |
Pages |
235319-235319,8 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Electron transport through a spin-orbit-coupled quantum ring is investigated within linear response theory. We show that the finite width of the ring results in the appearance of Fano resonances in the conductance. This turns out to be a consequence of the spin-orbit interaction that leads to a breaking of the parity of the states localized in the ring. The resonances appear when the system is close to maxima of Aharonov-Casher conductance oscillations where spin transfer is heavily modified. When the spin-orbit coupling strength is detuned from the Aharonov-Casher maxima the resonances are broadened resulting in a dependence of the spin transport on the electron Fermi energy in contrast to predictions from one-dimensional models. |
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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 |
000298605700002 |
Publication Date |
2011-12-29 |
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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 |
19 |
Open Access |
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Notes |
; This work was supported by the “Krakow Interdisciplinary PhD Project in Nanoscience and Advanced Nanostructures” operated within the Foundation for Polish Science MPD Programme cofinanced by the EU European Regional Development Fund, Project No. N N202103938 supported by the Ministry of Science and Higher Education (MNiSW) for 2010-2013, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-V1). This research was supported in part by PL-Grid Infrastructure. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:94292 |
Serial |
1171 |
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Permanent link to this record |
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Author |
Berger, J.; Milošević, M.V. |
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Title |
Fluctuations in superconducting rings with two order parameters |
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 |
84 |
Issue |
21 |
Pages |
214515-214515,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Motivated by two-band superconductivity in, e.g., borides and pnictides, starting from the two-band Ginzburg-Landau energy functional, we discuss how the presence of two order parameters and the coupling between them influence a superconducting ring in the fluctuative regime. Our method is an extension of the von OppenRiedel formalism for rings; it is exact, but requires numerical implementation. We also study approximations for which analytic expressions can be obtained, and check their ranges of validity. We provide estimates for the temperature ranges where fluctuations are important, calculate the persistent current in MgB2 rings as a function of temperature and enclosed flux, and point out its additional dependence on the cross-section area of the wire from which the ring is made. We find temperature regions in which fluctuations enhance the persistent currents and regions where they inhibit the persistent current. The presence of two order parameters that can fluctuate independently always leads to larger averages of the order parameters at Tc, but yields larger persistent current only for appropriate parameters. In cases of very different material parameters for the two coupled condensates, the persistent current is inhibited. |
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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 |
000297932500004 |
Publication Date |
2011-12-12 |
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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 research was supported by the Israel Science Foundation, Grant No. 249/10, the Flemish Science Foundation (FWO-Vl), and the ESF network INSTANS. We are grateful to Andrei Varlamov and Felix von Oppen for their answers to our enquiries. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93957 |
Serial |
1226 |
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Permanent link to this record |
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Author |
Xu, B.; Milošević, M.V.; Lin, S.-H.; Peeters, F.M.; Jankó, B. |
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Title |
Formation of multiple-flux-quantum vortices in mesoscopic superconductors from simulations of calorimetric, magnetic, and transport properties |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
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Volume |
107 |
Issue |
5 |
Pages |
057002,1-057002,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Because of strong flux confinement in mesoscopic superconductors, a giant vortex may appear in the ground state of the system in an applied magnetic field. This multiquanta vortex can then split into individual vortices (and vice versa) as a function of, e.g., applied current, magnetic field, or temperature. Here we show that such transitions can be identified by calorimetry, as the formation or splitting of a giant vortex results in a clear jump in measured heat capacity versus external drive. We attribute this phenomenon to an abrupt change in the density of states of the quasiparticle excitations in the vortex core(s), and further link it to a sharp change of the magnetic susceptibility at the transitionproving that the formation of a giant vortex can also be detected by magnetometry. |
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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 |
New York, N.Y. |
Editor |
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Language |
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Wos |
000293333100006 |
Publication Date |
2011-07-29 |
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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 |
0031-9007;1079-7114; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.462 |
Times cited |
26 |
Open Access |
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Notes |
; We thank O. Bourgeois, T. Yokoyama, M. Eschrig, and M. Ichioka for discussions. This work was supported by FWO-Vlaanderen, the Belgian Science Policy (IAP), the bilateral project Flanders-USA, NSF NIRT, ECS-0609249, and Institute of Theoretical Sciences, Notre Dame. ; |
Approved |
Most recent IF: 8.462; 2011 IF: 7.370 |
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Call Number |
UA @ lucian @ c:irua:91237 |
Serial |
1263 |
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Permanent link to this record |
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Author |
Tognalii, N.G.; Cortés, E.; Hernández-Nieves, A.D.; Carro, P.; Usaj, G.; Balseiro, C.A.; Vela, M.E.; Salvarezza, R.C.; Fainstein, A. |
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Title |
From single to multiple Ag-layer modification of Au nanocavity substrates : a tunable probe of the chemical surface-enhanced Raman scattering mechanism |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
ACS nano |
Abbreviated Journal |
Acs Nano |
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Volume |
5 |
Issue |
7 |
Pages |
5433-5443 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We present experimental and computational results that enlighten the mechanisms underlying the chemical contribution to surface-enhanced Raman scattering (SERS). Gold void metallic arrays electrochemically covered either by a Ag monolayer or 10100 Ag layers were modified with a self-assembled monolayer of 4-mercaptopyridine as a molecular Raman probe displaying a rich and unexpected Raman response. A resonant increase of the Raman intensity in the red part of the spectrum is observed that cannot be related to plasmon excitations of the cavity-array. Notably, we find an additional 1020 time increase of the SERS amplification upon deposition of a single Ag layer on the Au substrate, which is, however, almost quenched upon deposition of 10 atomic layers. Further deposition of 100 atomic Ag layers results in a new increase of the SERS signal, consistent with the improved plasmonic efficiency of Ag bulk-like structures. The SERS response as a function of the Ag layer thickness is analyzed in terms of ab initio calculations and a microscopic model for the SERS chemical mechanism based on a resonant charge transfer process between the molecular HOMO state and the Fermi level in the metal surface. We find that a rearrangement of the electronic charge density related to the presence of the Ag monolayer in the Au/Ag/molecule complex causes an increase in the distance between the HOMO center of charge and the metallic image plane that is responsible for the variation of Raman enhancement between the studied substrates. Our results provide a general platform for studying the chemical contribution to SERS, and for enhancing the Raman efficiency of tailored Au-SERS templates through electrochemical modification with Ag films. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000293035200019 |
Publication Date |
2011-06-15 |
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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 |
1936-0851;1936-086X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.942 |
Times cited |
26 |
Open Access |
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Notes |
; We acknowledge financial support from ANPCyT (Argentina, PICT08-1617, PICT08-2236, PICT06-621, PICT-CNPQ-08-0019, PAE 22711, PICT06-01061, PICT06-483) and Project CTQ2008-06017/BQU, Spain. N.G.T, E.C., A.D.H.N., R.C.S, G.U., C.A.B., and A.F. are also at CONICET. M.E.V. is a member of the research career of CIC BsAs. R.C.S., C.A.B., and A.F. are Guggenheim Foundation Fellows. We would like to thank Dr. M. H. Fonticelli for fruitful discussions on the electrochemical measurements and Dr. H. Pastoriza for the help with the SEM measurements. ; |
Approved |
Most recent IF: 13.942; 2011 IF: 11.421 |
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Call Number |
UA @ lucian @ c:irua:91775 |
Serial |
1285 |
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Permanent link to this record |
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Author |
Vandenberghe, W.; Sorée, B.; Magnus, W.; Fischetti, M.V. |
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Title |
Generalized phonon-assisted Zener tunneling in indirect semiconductors with non-uniform electric fields : a rigorous approach |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
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Volume |
109 |
Issue |
12 |
Pages |
124503-124503,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
A general framework to calculate the Zener current in an indirect semiconductor with an externally applied potential is provided. Assuming a parabolic valence and conduction band dispersion, the semiconductor is in equilibrium in the presence of the external field as long as the electron-phonon interaction is absent. The linear response to the electron-phonon interaction results in a non-equilibrium system. The Zener tunneling current is calculated from the number of electrons making the transition from valence to conduction band per unit time. A convenient expression based on the single particle spectral functions is provided, enabling the evaluation of the Zener tunneling current under any three-dimensional potential profile. For a one-dimensional potential profile an analytical expression is obtained for the current in a bulk semiconductor, a semiconductor under uniform field, and a semiconductor under a non-uniform field using the WKB (Wentzel-Kramers-Brillouin) approximation. The obtained results agree with the Kane result in the low field limit. A numerical example for abrupt p-n diodes with different doping concentrations is given, from which it can be seen that the uniform field model is a better approximation than the WKB model, but a direct numerical treatment is required for low bias conditions. |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000292331200134 |
Publication Date |
2011-06-21 |
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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 |
0021-8979; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.068 |
Times cited |
41 |
Open Access |
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Notes |
; William Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). ; |
Approved |
Most recent IF: 2.068; 2011 IF: 2.168 |
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Call Number |
UA @ lucian @ c:irua:90808 |
Serial |
1325 |
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Permanent link to this record |
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Author |
Engbarth, M.A.; Bending, S.J.; Milošević, M.V. |
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Title |
Geometry-driven vortex states in type-I superconducting Pb nanowires |
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 |
22 |
Pages |
224504-224504,7 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Hall probe magnetometry has been used to investigate the magnetization of individual cylindrically shaped Pb nanowires grown by electrocrystallization on a highly oriented pyrolytic graphite electrode. These measurements have been interpreted by comparison with three-dimensional Ginzburg-Landau (GL) calculations for nanowires with our sample parameters. We find that the measured superheating field and the critical field for surface superconductivity are strongly influenced by the temperature-dependent coherence length, ξ(T) and penetration depth λ(T) and their relationship to the nanowire diameter. As the temperature is increased toward Tc this drives a change in the superconductor-normal transition from first order irreversible to first order reversible and finally second order reversible. We find that the geometrical flux confinement in our type-I nanowires leads to the formation of a one-dimensional row of single-quantum vortices. While GL calculations show a quite uniform distribution of vortices in thin nanowires, clear vortex bunching is found as the diameter increases, suggesting a transition to a more classical type-I behavior. Subtle changes in minor magnetization loops also indicate that slightly different flux configurations can form with the same vorticity, which depend on the sample history. |
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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 |
000291888300012 |
Publication Date |
2011-06-21 |
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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 |
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 |
19 |
Open Access |
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Notes |
; We acknowledge valuable conversations with F. V. Kusmartsev and W. M. Wu at Loughborough University, UK. This work was supported by the EPSRC-UK under Grant No. EP/E039944/1, and the Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:90927 |
Serial |
1331 |
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Permanent link to this record |
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Author |
Galván Moya, J.E.; Peeters, F.M. |
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Title |
Ginzburg-Landau theory of the zigzag transition in quasi-one-dimensional classical Wigner crystals |
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 |
84 |
Issue |
13 |
Pages |
134106,1-134106,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We present a mean-field description of the zigzag phase transition of a quasi-one-dimensional system of strongly interacting particles, with interaction potential r−ne−r/λ, that are confined by a power-law potential (yα). The parameters of the resulting one-dimensional Ginzburg-Landau theory are determined analytically for different values of α and n. Close to the transition point for the zigzag phase transition, the scaling behavior of the order parameter is determined. For α=2, the zigzag transition from a single to a double chain is of second order, while for α>2, the one-chain configuration is always unstable and, for α<2, the one-chain ordered state becomes unstable at a certain critical density, resulting in jumps of single particles out of the chain. |
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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 |
000296289500004 |
Publication Date |
2011-10-18 |
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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 |
16 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93583 |
Serial |
1345 |
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Permanent link to this record |