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Author |
Nowak, M.P.; Szafran, B.; Peeters, F.M.; Partoens, B.; Pasek, W.J. |
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Title |
Tuning of the spin-orbit interaction in a quantum dot by an in-plane magnetic field |
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 |
24 |
Pages |
245324-245324,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using an exact-diagonalization approach we show that one- and two-electron InAs quantum dots exhibit an avoided crossing in the energy spectra that is induced by the spin-orbit coupling in the presence of an in-plane external magnetic field. The width of the avoided crossings depends strongly on the orientation of the magnetic field, which reveals the intrinsic anisotropy of the spin-orbit-coupling interactions. We find that for specific orientations of the magnetic field avoided crossings vanish. A value of this orientation can be used to extract the ratio of the strength of Rashba and Dresselhaus interactions. The spin-orbit anisotropy effects for various geometries and orientations of the confinement potential are discussed. Our analysis explains the physics behind the recent measurements performed on a gated self-assembled quantum dot [ S. Takahashi et al. Phys. Rev. Lett. 104 246801 (2010)]. |
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Wos |
000292254000005 |
Publication Date |
2011-06-30 |
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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 |
27 |
Open Access |
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Notes |
; The authors thank S. Takahashi for helpful discussions. This work was supported by the “Krakow Interdisciplinary PhD Project in Nanoscience and Advanced Nanostructures” operated within the Foundation for Polish Science MPD Programme co-financed by the EU European Regional Development Fund, the Project No. N N202103938 supported by the Ministry of Science an Higher Education (MNiSW) for 2010-2013, and the Belgian Science Policy (IAP). W. J. P. has been partially supported by the EU Human Capital Operation Program, Polish Project No. POKL.04.0101-00-434/08-00. Calculations were performed in ACK-CYFRONET-AGH on the RackServer Zeus. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:90923 |
Serial |
3755 |
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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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Wos |
000294226000013 |
Publication Date |
2011-08-25 |
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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 |
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 |
Vodolazov, D.Y.; Peeters, F.M. |
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Title |
Origin of the hysteresis of the current voltage characteristics of superconducting microbridges near the critical temperature |
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 |
9 |
Pages |
094511 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The current voltage (IV) characteristics of short [with length L less than or similar to xi(T)] and long [L >> xi(T)] microbridges are theoretically investigated near the critical temperature of the superconductor. Calculations are made in the nonlocal (local) limit when the inelastic relaxation length due to electron-phonon interactions L(in) = (D tau(in))(1/2) is larger (smaller) than the temperature-dependent coherence length xi(T) (D is the diffusion coefficient, tau(in) is the inelastic relaxation time of the quasiparticle distribution function). We find that, in both limits, the origin of the hysteresis in the IV characteristics is mainly connected with the large time scale over which the magnitude of the order parameter varies in comparison with the time-scale variation of the superconducting phase difference across the microbridge in the resistive state. In the nonlocal limit, the time-averaged heating and cooling of quasiparticles are found in different areas of the microbridge, which are driven, respectively, by oscillations of the order parameter and the electric field. We show that, by introducing an additional term in the time-dependent Ginzburg-Landau equation, it is possible to take into account the cooling effect in the local limit too. |
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Wos |
000294920900009 |
Publication Date |
2011-09-14 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
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Notes |
; This work was supported by the Russian Foundation for Basic Research, Russian Agency of Education under the Federal Target Programme“Scientific and educational personnel of innovative Russia in 2009-2013,” the Flemish Science Foundation (FWO-Vl), and the Belgian Science Policy (IAP). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:105573 |
Serial |
2527 |
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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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Wos |
000294777400013 |
Publication Date |
2011-09-09 |
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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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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 |
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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 |
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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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 |
Zha, G.-Q.; Milošević, M.V.; Zhou, S.-P.; Peeters, F.M. |
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Title |
Influence of impurities and surface defects on the flux-induced current in mesoscopic d-wave superconducting loops |
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 |
132501-132501,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigated the magnetic flux dependence of the supercurrent in mesoscopic d-wave superconducting loops, containing impurities and surface defects, by numerically solving the Bogoliubovde Gennes equations self-consistently. In the presence of impurities, bound states arise close to the Fermi energy. In the case of a single impurity, the flux-induced current is found to be suppressed. This can be different when more impurities are introduced in the sample due to the quantum interference effect, which depends sensitively on the relative position between the impurities. We further analyze the effect of small surface defects at the inner or outer edge of the loop, and show that indentation and bulge defects have pronounced and different effects on the supercurrent. |
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Wos |
000295713600002 |
Publication Date |
2011-10-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
13 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), by Belgian Science Policy (IAP), by National Science Foundation of China (Grant Nos. 10904089 and 60971053), and by research funds under Grant Nos. 20093108120005, S30105, 09JC1406000, and 10zz63. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:92811 |
Serial |
1623 |
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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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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 |
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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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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 |
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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 |
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 |
Sena, S.H.R.; Pereira, J.M.; Peeters, F.M.; Farias, G.A. |
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Title |
Landau levels in asymmetric graphene trilayer |
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 |
205448-205448,7 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The electronic spectrum of three coupled graphene layers (graphene trilayers) is investigated in the presence of an external magnetic field. We obtain analytical expressions for the Landau level spectrum for both the ABA and ABC type of stacking, which exhibit very different dependence on the magnetic field. We show that layer asymmetry and an external gate voltage can strongly influence the properties of the system. |
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Wos |
000297295400018 |
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 |
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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 |
30 |
Open Access |
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Notes |
; This work was supported by the Brazilian Council for Research (CNPq), the National Council for the Improvement of Higher Education (CAPES), the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the bilateral projects between Flanders and Brazil and the CNPq and FWO-Vl. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:94026 |
Serial |
1773 |
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Permanent link to this record |
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Author |
Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M.; Axt, V.M. |
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Title |
Parity-fluctuation induced enlargement of the ratio \DeltaE/kBTc in metallic grains |
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 |
214518-214518,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate how the interplay of quantum confinement and particle number-parity fluctuations affects superconducting correlations in ultra-small metallic grains. Using the number-parity projected BCS formalism we calculate the critical temperature and the excitation gap as a function of the grain size for grains with even and odd number of confined carriers. We show that the experimentally observed anomalous increase of the coupling ratio ΔE/kBTc with decreasing superconducting grain size can be attributed to an enhancement of the number-parity fluctuations in ultra-small grains. |
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Wos |
000298114100003 |
Publication Date |
2011-12-16 |
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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 |
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 |
14 |
Open Access |
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Notes |
; This work was supported by the European Community under a Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR), the Flamish Science Foundation (FWO-Vl), and the Belgian Science Policy (IAP). M. D. C. thanks A. S. Mel'nikov and N. B. Kopnin for fruitful discussions. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:94373 |
Serial |
2555 |
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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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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 |
Covaci, L.; Peeters, F.M. |
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Title |
Superconducting proximity effect in graphene under inhomogeneous strain |
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 |
241401-241401,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The interplay between quantum Hall states and Cooper pairs is usually hindered by the suppression of the superconducting state due to the strong magnetic fields needed to observe the quantum Hall effect. From this point of view, graphene is special since it allows the creation of strong pseudomagnetic fields due to strain. We show that in a Josephson junction made of strained graphene, Cooper pairs will diffuse into the strained region. The pair correlation function will be sublattice polarized due to the polarization of the local density of states in the zero pseudo-Landau level. We uncover two regimes: (1) one in which the cyclotron radius is larger than the junction length, in which case the supercurrent will be enhanced, and (2) the long junction regime where the supercurrent is strongly suppressed because the junction becomes an insulator. In the latter case quantized Hall states form and Andreev scattering at the normal/superconducting interface will induce edge states. Our numerical calculation has become possible due to an extension of the Chebyshev-Bogoliubovde Gennes method to computations on video cards (GPUs). |
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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 |
000297766600003 |
Publication Date |
2011-12-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
27 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Euro GRAPHENE project CONGRAN. Discussions with Andrey Chaves are gratefully acknowledged. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93962 |
Serial |
3364 |
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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 |
Masir, M.R.; Matulis, A.; Peeters, F.M. |
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Title |
Scattering of Dirac electrons by circular mass barriers : valley filter and resonant scattering |
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 |
245413-245413,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The scattering of two-dimensional (2D) massless Dirac electrons is investigated in the presence of a random array of circular mass barriers. The inverse momentum relaxation time and the Hall factor are calculated and used to obtain parallel and perpendicular resistivity components within linear transport theory. We found a nonzero perpendicular resistivity component which has opposite sign for electrons in the different K and K′ valleys. This property can be used for valley filter purposes. The total cross section for scattering on penetrable barriers exhibits resonances due to the presence of quasibound states in the barriers that show up as sharp gaps in the cross section while for Schrödinger electrons they appear as peaks. |
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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 |
000297934500008 |
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 |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
32 |
Open Access |
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|
Notes |
; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:94383 |
Serial |
2951 |
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Permanent link to this record |
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Author |
Latimer, M.L.; Berdiyorov, G.R.; Xiao, Z.L.; Kwok, W.K.; Peeters, F.M. |
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Title |
Vortex interaction enhanced saturation number and caging effect in a superconducting film with a honeycomb array of nanoscale holes |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
1 |
Pages |
012505-012505,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The electrical transport properties of a MoGe thin film with a honeycomb array of nanoscale holes are investigated. The critical current of the system shows nonmatching anomalies as a function of applied magnetic field, enabling us to distinguish between multiquanta vortices trapped in the holes and interstitial vortices located between the holes. The number of vortices trapped in each hole is found to be larger than the saturation number predicted for an isolated hole and shows a nonlinear field dependence, leading to the caging effect as predicted from the Ginzburg-Landau (GL) theory. Our experimental results are supplemented by numerical simulations based on the GL theory. |
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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 |
000299867200001 |
Publication Date |
2012-01-26 |
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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 |
41 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP) (theory) and by the US Department of Energy (DOE) Grant No. DE-FG02-06ER46334 (experiment). G. R. B. acknowledges an individual grant from FWO-Vl. W. K. K. acknowledges support from DOE BES under Contract No. DE-AC02-06CH11357, which also funds Argonne's Center for Nanoscale Materials (CNM), where the focused-ion-beam milling was performed. M.L.L was a recipient of the NIU/ANL Distinguished Graduate Fellowship. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:96224 |
Serial |
3866 |
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Permanent link to this record |
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Author |
Vagov, A.V.; Shanenko, A.A.; Milošević, M.V.; Axt, V.M.; Peeters, F.M. |
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Title |
Extended Ginzburg-Landau formalism : systematic expansion in small deviation from the critical temperature |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
1 |
Pages |
014502-014502,17 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Based on the Gor'kov formalism for a clean s-wave superconductor, we develop an extended version of the single-band Ginzburg-Landau (GL) theory by means of a systematic expansion in the deviation from the critical temperature T(c), i.e., tau = 1 – T/T(c). We calculate different contributions to the order parameter and the magnetic field: the leading contributions (proportional to tau(1/2) in the order parameter and. t in the magnetic field) are controlled by the standard GL theory, while the next-to-leading terms (proportional to tau(3/2) in the gap and proportional to tau(2) in the magnetic field) constitute the extended GL (EGL) approach. We derive the free-energy functional for the extended formalism and the corresponding expression for the current density. To illustrate the usefulness of our formalism, we calculate, in a semianalytical form, the temperature-dependent correction to the GL parameter at which the surface energy becomes zero, and analytically, the temperature dependence of the thermodynamic critical field. We demonstrate that the EGL formalism is not just a mathematical extension to the theory: variations of both the gap and the thermodynamic critical field with temperature calculated within the EGL theory are found in very good agreement with the full BCS results down to low temperatures, which dramatically improves the applicability of the formalism compared to its standard predecessor. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000298985100002 |
Publication Date |
2012-01-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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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 |
36 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). A. V. V. is grateful to V. Zalipaev for important comments. A. A. S. thanks W. Pogosov for helpful notes. Discussions with E. H. Brandt and A. Perali are appreciated. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:96232 |
Serial |
1155 |
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Permanent link to this record |
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Author |
Vodolazov, D.Y.; Peeters, F.M. |
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Title |
Enhancement of the retrapping current of superconducting microbridges of finite length |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
2 |
Pages |
024508-024508,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We theoretically find that the resistance of a superconducting microbridge or nanowire decreases while the retrapping current I(r) for the transition to the superconducting state increases when one suppresses the magnitude of the order parameter vertical bar Delta vertical bar in the attached superconducting leads. This effect is a consequence of the increased energy interval for diffusion of the “hot” nonequilibrium quasiparticles (induced by the oscillations of vertical bar Delta vertical bar in the center of the microbridge) to the leads. The effect is absent in short microbridges (with length less than the coherence length) and it is relatively weak in long microbridges (with length larger than the inelastic relaxation length of the nonequilibrium distribution function). A nonmonotonous dependence of I(r) on the length of the microbridge is predicted. Our results are important for the explanation of the enhancement of the critical current and the appearance of negative magnetoresistance observed in many recent experiments on superconducting microbridges or nanowires. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000298863400005 |
Publication Date |
2012-01-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
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Notes |
; This work was supported by the Russian Foundation for Basic Research, Russian Agency of Education, under the Federal Target Programme “Scientific and Educational Personnel of Innovative Russia in 2009-2013” and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:96235 |
Serial |
1065 |
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Permanent link to this record |
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Author |
Nasr Esfahani, D.; Covaci, L.; Peeters, F.M. |
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Title |
Electric-field-induced shift of the Mott metal-insulator transition in thin films |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
8 |
Pages |
085110-085110,8 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The ground-state properties of a paramagnetic Mott insulator at half-filling are investigated in the presence of an external electric field using the inhomogeneous Gutzwiller approximation for a single-band Hubbard model in a slab geometry. We find that the metal-insulator transition is shifted toward higher Hubbard repulsions by applying an electric field perpendicular to the slab. The main reason is the accumulation of charges near the surface. The spatial distribution of site-dependent quasiparticle weight shows that it is maximal in a few layers beneath the surface, while the central sites where the field is screened have a very low quasiparticle weight. Our results show that above a critical-field value, states near the surface will be metallic, while the bulk quasiparticle weight is extremely suppressed but never vanishing, even for large Hubbard repulsions above the bulk zero-field critical value. Below the critical-field value, our results hint toward an insulating state in which the electric field is totally screened and the slab is again at half-filling. |
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Place of Publication |
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Language |
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Wos |
000300240100002 |
Publication Date |
2012-02-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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 |
3 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and the Belgian Science Policy (IAP). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:97208 |
Serial |
884 |
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Permanent link to this record |
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Author |
Krstajić, P.M.; Peeters, F.M. |
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Title |
Remote electron plasmon polaron in graphene |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
8 |
Pages |
085436-085436,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The Coulomb interaction and the correlation of a remote electron with a single layer of graphene is investigated in the presence of a magnetic field applied perpendicular to the graphene layer. The remote electron polarizes the electron gas in the graphene layer, which we describe in terms of excitations of virtual plasmons in graphene. The composite quasiparticle formed by electron plus polarization is called a plasmon polaron. The ground-state energy of this quasiparticle is calculated within perturbation theory for remote electrons in different environments. |
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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 |
000300831900012 |
Publication Date |
2012-02-27 |
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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 |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:97202 |
Serial |
2869 |
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Permanent link to this record |
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Author |
Berdiyorov, G.R.; Hernández-Nieves, A.D.; Milošević, M.V.; Peeters, F.M.; Dominguez, D. |
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Title |
Flux-quantum-discretized dynamics of magnetic flux entry, exit, and annihilation in current-driven mesoscopic type-I superconductors |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
9 |
Pages |
092502-092502,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We study nonlinear flux dynamics in a current-carrying type-I superconductor. The stray magnetic field of the current induces the intermediate state, where nucleation of flux domains is discretized to a single fluxoid at a time, while their final shape (tubular or laminar), size, and nucleation rate depend on applied current and edge conditions. The current induces opposite flux domains on opposite sides of the sample, and subsequently drives them to annihilation-which is also discretized, as a sequence of vortex-antivortex pairs. The discretization of both nucleation and annihilation leaves measurable traces in the voltage across the sample and in locally probed magnetization. The reported dynamic phenomena thus provide an unambiguous proof of a flux quantum being the smallest building block of the intermediate state in type-I superconductors. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000301183000002 |
Publication Date |
2012-03-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
14 |
Open Access |
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Notes |
; This work was supported by the Belgian Science Policy (IAP), the Flemish Science Foundation (FWO-Vl), and the collaborative project FWO-MINCyT (Project No. FW/08/01). G. R. B. and A. D. H acknowledge support from FWO-Vl. A. D. H. and D. D. acknowledge support from CONICET, CNEA, and ANPCyT (Grant No. PICT07-824). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:97180 |
Serial |
1243 |
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Permanent link to this record |
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Author |
Verberck, B.; Partoens, B.; Peeters, F.M.; Trauzettel, B. |
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Title |
Strain-induced band gaps in bilayer graphene |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
12 |
Pages |
125403-125403,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We present a tight-binding investigation of strained bilayer graphene within linear elasticity theory, focusing on the different environments experienced by the A and B carbon atoms of the different sublattices. We find that the inequivalence of the A and B atoms is enhanced by the application of perpendicular strain epsilon(zz), which provides a physical mechanism for opening a band gap, most effectively obtained when pulling the two graphene layers apart. In addition, perpendicular strain introduces electron-hole asymmetry and can result in linear electronic dispersion near the K point. Our findings suggest experimental means for strain-engineered band gaps in bilayer graphene. |
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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 |
000301113200005 |
Publication Date |
2012-03-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
53 |
Open Access |
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|
Notes |
; The authors would like to acknowledge O. Leenaerts, E. Mariani, K. H. Michel, and J. Schelter for useful discussions. B. V. was financially supported by the Flemish Science Foundation (FWO-Vl). This work was financially supported by the ESF program EuroGraphene under projects CONGRAN and ENTS as well as by the DFG. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:97181 |
Serial |
3168 |
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Permanent link to this record |
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Author |
Saniz, R.; Partoens, B.; Peeters, F.M. |
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Title |
Green function approach to superconductivity in nanowires |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
14 |
Pages |
144504-144504,7 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Superconductivity in nanowires made of weak coupling superconductor materials is investigated using a Green function approach. We show that these are multigap systems in which the ratio Delta(T)/k(B)T(c) is to a large extent similar to what is observed in some high-T-c two-gap systems, such as MgB2 and some of the Fe-based superconductors. On the other hand, because of confinement, the superfluid density has a temperature behavior of the form n(s)(T) = 1 – (T/T-c)(3) near T-c, thus deviating from the BCS behavior for bulk superconductors. |
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Thesis |
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Place of Publication |
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Editor |
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Language |
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Wos |
000302290700006 |
Publication Date |
2012-04-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.836 |
Times cited |
1 |
Open Access |
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|
Notes |
; This work was supported by FWO-Vl and the Belgian Science Policy (IAP). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:97764 |
Serial |
1381 |
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Permanent link to this record |
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Author |
Clem, J.R.; Mawatari, Y.; Berdiyorov, G.R.; Peeters, F.M. |
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Title |
Predicted field-dependent increase of critical currents in asymmetric superconducting nanocircuits |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
14 |
Pages |
144511-144511,16 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The critical current of a thin superconducting strip of width W much larger than the Ginzburg-Landau coherence length xi but much smaller than the Pearl length Lambda = 2 lambda(2)/d is maximized when the strip is straight with defect-free edges. When a perpendicular magnetic field is applied to a long straight strip, the critical current initially decreases linearly with H but then decreases more slowly with H when vortices or antivortices are forced into the strip. However, in a superconducting strip containing sharp 90 degrees or 180 degrees turns, the zero-field critical current at H = 0 is reduced because vortices or antivortices are preferentially nucleated at the inner corners of the turns, where current crowding occurs. Using both analytic London-model calculations and time-dependent Ginzburg-Landau simulations, we predict that in such asymmetric strips the resulting critical current can be increased by applying a perpendicular magnetic field that induces a current-density contribution opposing the applied current density at the inner corners. This effect should apply to all turns that bend in the same direction. |
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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 |
000302611100004 |
Publication Date |
2012-04-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
40 |
Open Access |
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Notes |
; This research, supported in part by the US Department of Energy, Office of Basic Energy Science, Division of Materials Sciences and Engineering, was performed in part at the Ames Laboratory, which is operated for the US Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358. This work also was supported in part by the Flemish Science Foundation (FWO-Vlaanderen) and the Belgian Science Policy (IAP). G.R.B. acknowledges individual support from FWO-Vlaanderen. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:98263 |
Serial |
2695 |
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Permanent link to this record |
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Author |
Shakouri, K.; Szafran, B.; Esmaeilzadeh, M.; Peeters, F.M. |
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Title |
Effective spin-orbit interaction Hamiltonian for quasi-one-dimensional quantum rings |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
16 |
Pages |
165314-165314,8 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The effective Hamiltonian for an electron in a quasi-one-dimensional quantum ring in the presence of spin-orbit interactions is derived. We demonstrate that, when both coupling types are simultaneously present, the effective Hamiltonian derived by the lowest-radial-state approximation produces energy spectra and charge densities which deviate strongly from the exact ones. For equal Rashba and Dresselhaus coupling constants the lowest-radial-state approximation opens artifactal avoided crossings in the energy spectra and deforms the circular symmetry of the confined charge densities. In this case, there does not exist a ring thin enough to justify the restriction to the lowest radially quantized energy state. We derive the effective Hamiltonian accounting for both the lowest and the first excited radial states, and show that the inclusion of the latter restores the correct features of the exact solution. Relation of this result to the states of a quantum wire is also discussed. |
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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 |
000303068800006 |
Publication Date |
2012-04-20 |
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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 |
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 |
32 |
Open Access |
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|
Notes |
; This work was partially supported by Polish Ministry of Science and Higher Education and its grants for Scientific Research. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:98258 |
Serial |
855 |
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Permanent link to this record |
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Author |
Badalyan, S.M.; Peeters, F.M. |
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Title |
Effect of nonhomogenous dielectric background on the plasmon modes in graphene double-layer structures at finite temperatures |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
19 |
Pages |
195444-195444,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We have calculated the plasmon modes in graphene double layer structures at finite temperatures, taking into account the inhomogeneity of the dielectric background of the system. The effective dielectric function is obtained from the solution of the Poisson equation of a three-layer dielectric medium with graphene sheets located at the interfaces, separating the different materials. Due to the momentum dispersion of the effective dielectric function, the intra- and interlayer bare Coulomb interactions in the graphene double layer system acquires an additional momentum dependence-an effect that is of the order of the interlayer interaction itself. We show that the energies of the in-phase and out-of-phase plasmon modes are determined largely by different values of the spatially dependent effective dielectric function. The effect of the dielectric inhomogeneity increases with temperature, and even at high temperatures the energy shift induced by the dielectric inhomogeneity and temperature itself remains larger than the broadening of the plasmon energy dispersions due to the Landau damping. The obtained new features of the plasmon dispersions can be observed in frictional drag measurements and in inelastic light scattering and electron energy-loss spectroscopies. |
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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 |
000304394800011 |
Publication Date |
2012-05-23 |
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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 |
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 |
67 |
Open Access |
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|
Notes |
; We thank G. Vignale for useful discussions and acknowledge support from the Flemisch Science Foundation (FWO-Fl) and the Belgian Science Policy (BELSPO). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:98941 |
Serial |
826 |
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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 |
Strain-engineered graphene through a nanostructured substrate : 1 : deformations |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
19 |
Pages |
195445-195445,11 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using atomistic simulations we investigate the morphological properties of graphene deposited on top of a nanostructured substrate. Sinusoidally corrugated surfaces, steps, elongated trenches, one-dimensional and cubic barriers, spherical bubbles, Gaussian bumps, and Gaussian depressions are considered as support structures for graphene. The graphene-substrate interaction is governed by van der Waals forces and the profile of the graphene layer is determined by minimizing the energy using molecular dynamics simulations. Based on the obtained optimum configurations, we found that (i) for graphene placed over sinusoidally corrugated substrates with corrugation wavelengths longer than 2 nm, the graphene sheet follows the substrate pattern while for supported graphene it is always suspended across the peaks of the substrate, (ii) the conformation of graphene to the substrate topography is enhanced when increasing the energy parameter in the van der Waals model, (iii) the adhesion of graphene into the trenches depends on the width of the trench and on the graphene's orientation, i. e., in contrast to a small-width (3 nm) nanoribbon with armchair edges, the one with zigzag edges follows the substrate profile, (iv) atomic-scale graphene follows a Gaussian bump substrate but not the substrate with a Gaussian depression, and (v) the adhesion energy due to van der Waals interaction varies in the range [0.1-0.4] J/m(2). |
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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 |
000304394800012 |
Publication Date |
2012-05-23 |
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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 |
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 |
62 |
Open Access |
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Notes |
; We thank L. Covaci and S. Costamagna for valuable comments. We acknowledge M. Zarenia, M. R. Masir and D. Nasr for fruitful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl) and ESF EUROCORE program EuroGRAPHENE: CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:98942 |
Serial |
3166 |
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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 |
Strain-engineered graphene through a nanostructured substrate : 2 : pseudomagnetic fields |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
19 |
Pages |
195446-195446,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The strain-induced pseudomagnetic field in supported graphene deposited on top of a nanostructured substrate is investigated by using atomistic simulations. A step, an elongated trench, a one-dimensional barrier, a spherical bubble, a Gaussian bump, and a Gaussian depression are considered as support structures for graphene. From the obtained optimum configurations we found very strong induced pseudomagnetic fields which can reach up to similar to 1000 T due to the strain-induced deformations in the supported graphene. Different magnetic confinements with controllable geometries are found by tuning the pattern of the substrate. The resulting induced magnetic fields for graphene on top of a step, barrier, and trench are calculated. In contrast to the step and trench the middle part of graphene on top of a barrier has zero pseudomagnetic field. This study provides a theoretical background for designing magnetic structures in graphene by nanostructuring substrates. We found that altering the radial symmetry of the deformation changes the sixfold symmetry of the induced pseudomagnetic field. |
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Corporate Author |
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Place of Publication |
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Wos |
000304394800013 |
Publication Date |
2012-05-23 |
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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 |
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 |
31 |
Open Access |
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the ESF EUROCORE program EuroGRAPHENE: CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:98943 |
Serial |
3167 |
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Permanent link to this record |
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Author |
Badalyan, S.M.; Peeters, F.M. |
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Title |
Electron-phonon bound state in graphene |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
20 |
Pages |
205453-205453,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The fine structure of the Dirac energy spectrum in graphene induced by electron-optical phonon coupling is investigated in the portion of the spectrum near the phonon emission threshold. The derived new dispersion equation in the immediate neighborhood below the threshold corresponds to an electron-phonon bound state. We find that the singular vertex corrections beyond perturbation theory strongly increase the electron-phonon binding energy scale. The predicted enhancement of the effective electron-phonon coupling can be measured using angle-resolved spectroscopy. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000304649400002 |
Publication Date |
2012-05-30 |
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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 |
12 |
Open Access |
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Notes |
; We thank E. Rashba for the useful discussion and acknowledge support from the Belgian Science Policy (IAP) and BELSPO. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:98939 |
Serial |
982 |
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Permanent link to this record |
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Author |
Krstajić, P.M.; Peeters, F.M. |
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Title |
Energy-momentum dispersion relation of plasmarons in graphene |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
20 |
Pages |
205454-205454,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The many-body correction to the band structure of a quasi-free-standing graphene layer is obtained within the Overhauser approach, where the electron-plasmon interaction is described as a field theoretical problem. We find that the Dirac-like spectrum is shifted by Delta E(k = 0), which is on the order of 50-150 meV, depending on the electron concentration n(e), and is in semiquantitative agreement with experimental data. The value of the Fermi velocity is renormalized by several percents and decreases with increasing electron concentration as found experimentally. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000304649900004 |
Publication Date |
2012-06-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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 |
11 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the ESF-EuroGRAPHENE project CON-GRAN, and the Serbian Ministry of Education and Science (project No. TR 32008). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:98937 |
Serial |
1043 |
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Permanent link to this record |
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Author |
Chen, Y.; Shanenko, A.A.; Peeters, F.M. |
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Title |
Superconducting transition temperature of Pb nanofilms : impact of thickness-dependent oscillations of the phonon-mediated electron-electron coupling |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
85 |
Issue |
22 |
Pages |
224517-224517,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
To date, several experimental groups reported measurements of the thickness dependence of T-c of atomically uniform single-crystalline Pb nanofilms. The reported amplitude of the T-c oscillations varies significantly from one experiment to another. Here we propose that the reason for this unresolved issue is an interplay of the quantum-size variations in the single-electron density of states with thickness-dependent oscillations in the phonon-mediated electron-electron coupling. Such oscillations in the coupling depend on the substrate material, the quality of the interface, the protection cover, and other details of the fabrication process, changing from one experiment to another. This explains why the available data do not exhibit one-voice consistency about the amplitude of the T-c oscillations. Our analyses are based on a numerical solution of the Bogoliubov-de Gennes equations for a superconducting slab. |
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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 |
000305251300006 |
Publication Date |
2012-06-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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 |
24 |
Open Access |
|
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|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:99076 |
Serial |
3368 |
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Permanent link to this record |