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Records |
Links |
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Author |
Földi, P.; Benedict, M.G.; Kalman, O.; Peeters, F.M. |
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| |
Title |
Quantum rings with time-dependent spin-orbit coupling: Spintronic Rabi oscillations and conductance properties |
Type |
A1 Journal article |
| |
Year  |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
80 |
Issue |
16 |
Pages |
165303,1-165303,10 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The strength of the (Rashba-type) spin-orbit coupling in mesoscopic semiconductor rings can be tuned with external gate voltages. Here we consider the case of a periodically changing spin-orbit interaction strength in time as induced by sinusoidal voltages. In a closed one dimensional quantum ring with weak spin-orbit coupling, Rabi oscillations are shown to appear. We find that the time evolution of initially localized wave packets exhibits a series of collapse and revival phenomena. Partial revivalsthat are typical in nonlinear systemsare shown to correspond to superpositions of states localized at different spatial positions along the ring. These spintronic Schrödinger-cat states appear periodically, and similarly to their counterparts in other physical systems, they are found to be sensitive to disturbances caused by the environment. The time-dependent spin transport problem, when leads are attached to the ring, is also solved. We show that the sideband currents induced by the oscillating spin-orbit interaction strength can become the dominant output channel, even in the presence of moderate thermal fluctuations and random scattering events. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000271352100078 |
Publication Date |
2009-10-12 |
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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 |
26 |
Open Access |
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| |
Notes |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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| |
Call Number |
UA @ lucian @ c:irua:80002 |
Serial |
2784 |
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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 |
Quasibound states of Schrödinger and Dirac electrons in a magnetic quantum dot |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
79 |
Issue |
15 |
Pages |
155451,1-155451,8 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The properties of a two-dimensional electron are investigated in the presence of a circular step magnetic-field profile. Both electrons with parabolic dispersion as well as Dirac electrons with linear dispersion are studied. We found that in such a magnetic quantum dot no electrons can be confined. Nevertheless close to the Landau levels quasibound states can exist with a rather long lifetime. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000265944200140 |
Publication Date |
2009-04-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.836 |
Times cited |
55 |
Open Access |
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| |
Notes |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:77026 |
Serial |
2800 |
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| Permanent link to this record |
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Author |
Zhang, Z.Z.; Wu, Z.H.; Chang, K.; Peeters, F.M. |
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Title |
Resonant tunneling through S- and U-shaped graphene nanoribbons |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
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| |
Volume |
20 |
Issue |
41 |
Pages |
415203,1-415203,7 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We theoretically investigate resonant tunneling through S- and U-shaped nanostructured graphene nanoribbons. A rich structure of resonant tunneling peaks is found emanating from different quasi-bound states in the middle region. The tunneling current can be turned on and off by varying the Fermi energy. Tunability of resonant tunneling is realized by changing the width of the left and/or right leads and without the use of any external gates. |
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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 |
Bristol |
Editor |
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Language |
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Wos |
000269930100007 |
Publication Date |
2009-09-17 |
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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 |
0957-4484;1361-6528; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.44 |
Times cited |
32 |
Open Access |
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| |
Notes |
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Approved |
Most recent IF: 3.44; 2009 IF: 3.137 |
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Call Number |
UA @ lucian @ c:irua:79311 |
Serial |
2893 |
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| Permanent link to this record |
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Author |
Austing, D.G.; Payette, C.; Nair, S.V.; Yu, G.; Gupta, J.A.; Partoens, B.; Amaha, S.; Tarucha, S. |
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Title |
Scheme for coherently quenching resonant current in a three-level quantum dot energy level mixer |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physica status solidi: C: conferences and critical reviews |
Abbreviated Journal |
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| |
Volume |
6 |
Issue |
4 |
Pages |
940-943 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We outline a scheme to create a dark state by three-level mixing that is potentially a useful tool for quantum coherent transport. Magnetic-field-induced intra-dot level mixing can lead to rich quantum superposition phenomena between three approaching single-particle states in a quantum dot when probed by the ground state of an adjacent weakly coupled quantum dot in the single-electron resonant tunnelling regime. The mixing relies on non-negligible anharmonicity and anisotropy in confining potentials of realistic quantum dots. Anti-crossing and transfer of strengths between resonances can be understood with a simple coherent level mixing model. Superposition can lead to the formation of a dark state by complete cancellation of an otherwise strong resonance. This is an all-electrical analogue of coherent population trapping seen in three-level-systems from quantum and atom optics. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Berlin |
Editor |
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Language |
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Wos |
000266597600040 |
Publication Date |
2008-12-12 |
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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 |
1862-6351;1610-1642; |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
|
Times cited |
|
Open Access |
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| |
Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:86927 |
Serial |
2953 |
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| Permanent link to this record |
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Author |
Geurts, R.; Milošević, M.V.; Peeters, F.M. |
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Title |
Second generation of vortex-antivortex states in mesoscopic superconductors: stabilization by artificial pinning |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
79 |
Issue |
17 |
Pages |
174508,1-174508,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Antagonistic symmetries of superconducting polygons and their induced multivortex states in a homogeneous magnetic field may lead to the appearance of antivortices in the vicinity of the superconducting/normal-state boundary (where mesoscopic confinement is particularly strong). Resulting vortex-antivortex (V-Av) molecules match the sample symmetry but are extremely sensitive to defects and fluctuations and remain undetected experimentally. Here we show that V-Av states can reappear deep in the superconducting state due to an array of perforations in a polygonal setting, surrounding a central hole. Such states are no longer caused by the symmetry of the sample but rather by pinning itself, which prevents the vortex-antivortex annihilation. As a result, even micron size, clearly spaced V-Av molecules can be stabilized in large mesoscopic samples. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000266501100098 |
Publication Date |
2009-05-06 |
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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 |
17 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:77399 |
Serial |
2956 |
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| Permanent link to this record |
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Author |
Szafran, B.; Nowak, M.P.; Bednarek, S.; Chwiej, T.; Peeters, F.M. |
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Title |
Selective suppression of Dresselhaus or Rashba spin-orbit coupling effects by the Zeeman interaction in quantum dots |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
79 |
Issue |
23 |
Pages |
235303,1-235303,13 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We study single- and two-electron parabolic quantum dots in the presence of linear Dresselhaus and Rashba spin-orbit interactions. Contributions of both types of spin-orbit coupling are investigated in the context of the spin polarization of the system at high magnetic fields. We demonstrate that for negative Landé factors the effect of the Dresselhaus coupling is suppressed at high magnetic field, which for structures without inversion asymmetry leads to a completely spin-polarized system and a strict antisymmetry of the wave functions with respect to the interchange of spatial-electron coordinates. For negative Landé factor the Rashba coupling is preserved at high field and consequently the spin polarization of the systems as well as the spatial antisymmetry of the two-electron wave function remain approximate. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000267699500073 |
Publication Date |
2009-06-02 |
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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 |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:77691 |
Serial |
2969 |
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| Permanent link to this record |
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Author |
Hao, Y.L.; Djotyan, A.P.; Avetisyan, A.A.; Peeters, F.M. |
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Title |
Shallow donor states near a semiconductor-insulator-metal interface |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
80 |
Issue |
3 |
Pages |
035329,1-035329,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The lowest energy electronic states of a donor located near a semiconductor-insulator-metal interface are investigated within the effective mass approach. The effect of the finite thickness of the insulator between the semiconductor and the metallic gate on the energy levels is studied. The lowest energy states are obtained through a variational approach, which takes into account the influence of all image charges that arise due to the presence of the metallic and the dielectric interfaces. We compare our results with a numerical exact calculation using the finite element technique. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000268617800101 |
Publication Date |
2009-07-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.836 |
Times cited |
22 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:77950 |
Serial |
2989 |
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| Permanent link to this record |
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Author |
Földi, P.; Kálmán, O.; Peeters, F.M. |
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Title |
Stability of spintronic devices based on quantum ring networks |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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Volume |
80 |
Issue |
12 |
Pages |
125324,1-125324,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Transport properties in mesoscopic networks are investigated, where the strength of the (Rashba-type) spin-orbit coupling is tuned with external gate voltages. We analyze in detail to what extent the ideal behavior and functionality of some promising network-based devices are modified by random (spin-dependent) scattering events and by thermal fluctuations. It is found that although the functionality of these devices is obviously based on the quantum coherence of the transmitted electrons, there is a certain stability: moderate level of errors can be tolerated. For mesoscopic networks made of typical semiconductor materials, we found that when the energy distribution of the input carriers is narrow enough, the devices can operate close to their ideal limits even at relatively high temperature. As an example, we present results for two different networks: one that realizes a Stern-Gerlach device and another that simulates a spin quantum walker. Finally we propose a simple network that can act as a narrow band energy filter even in the presence of random scatterers. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000270383300091 |
Publication Date |
2009-09-23 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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 |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:79230 |
Serial |
3131 |
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| Permanent link to this record |
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Author |
Yang, W.; Nelissen, K.; Kong, M.; Zeng, Z.; Peeters, F.M. |
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Title |
Structure of binary colloidal systems confined in a quasi-one-dimensional channel |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics |
Abbreviated Journal |
Phys Rev E |
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Volume |
79 |
Issue |
4 |
Pages |
041406,1-041406,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The structural properties of a binary colloidal quasi-one-dimensional system confined in a narrow channel are investigated through modified Monte Carlo simulations. Two species of particles with different magnetic moment interact through a repulsive dipole-dipole force are confined in a quasi-one-dimensional channel. The impact of three decisive parameters (the density of particles, the magnetic-moment ratio, and the fraction between the two species) on the transition from disordered phase to crystal-like phases and the transitions among the different mixed phases are summarized in a phase diagram. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000265941300077 |
Publication Date |
2009-04-23 |
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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 |
1539-3755;1550-2376; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.366 |
Times cited |
11 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.366; 2009 IF: 2.400 |
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Call Number |
UA @ lucian @ c:irua:77021 |
Serial |
3308 |
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| Permanent link to this record |
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Author |
de Backer, J.W.; Vos, W.G.; Burnell, P.; Verhulst, S.L.; Salmon, P.; de Clerck, N.; de Backer, W. |
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Title |
Study of the variability in upper and lower airway morphology in Sprague-Dawley rats using modern micro-CT scan-based segmentation techniques |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
The anatomical record: advances in integrative anatomy and evolutionary biology |
Abbreviated Journal |
Anat Rec |
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Volume |
292 |
Issue |
5 |
Pages |
720-727 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
Animal models are being used extensively in pre-clinical and safety assessment studies to assess the effectiveness and safety of new chemical entities and delivery systems. Although never entirely replacing the need for animal testing, the use of computer simulations could eventually reduce the amount of animals needed for research purposes and refine the data acquired from the animal studies. Computational fluid dynamics is a powerful tool that makes it possible to simulate flow and particle behavior in animal or patient-specific respiratory models, for purposes of inhaled delivery. This tool requires an accurate representation of the respiratory system, respiration and dose delivery attributes. The aim of this study is to develop a representative airway model of the Sprague-Dawley rat using static and dynamic micro-CT scans. The entire respiratory tract was modeled, from the snout and nares down to the central airways at the point where no distinction could be made between intraluminal air and the surrounding tissue. For the selection of the representative model, variables such as upper airway movement, segmentation length, airway volume and size are taken into account. Dynamic scans of the nostril region were used to illustrate the characteristic morphology of this region in anaesthetized animals. It could be concluded from this study that it was possible to construct a highly detailed representative model of a Sprague-Dawley rat based on imaging modalities such as micro-CT scans |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000265766000010 |
Publication Date |
2009-03-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-8486;1932-8494; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
1.431 |
Times cited |
16 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.431; 2009 IF: 1.490 |
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Call Number |
UA @ lucian @ c:irua:76455 |
Serial |
3342 |
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| Permanent link to this record |
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Author |
Croitoru, M.D.; Shanenko, A.A.; Kaun, C.C.; Peeters, F.M. |
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Title |
Superconducting nanowires: interplay of discrete transverse modes with supercurrent |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
80 |
Issue |
2 |
Pages |
024513,1-024513,11 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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| |
Abstract |
From a numerical solution of the Bogoliubov-de Gennes equations, we investigate an interplay of the transverse discrete modes with a longitudinal supercurrent in a metallic cylindrical superconducting nanowire. The superconductor-to-normal transition induced by a longitudinal superflow of electrons is found to occur as a cascade of jumps in the order parameter (supercurrent and superfluid density) as a function of the superfluid velocity for diameters d<1015 nm (for Al parameters) and sufficiently low temperatures T<0.30.4Tc, with Tc the critical temperature. When approaching Tc, the jumps are smoothed into steplike but continuous drops. A similar picture occurs for d>1520 nm. Only when the diameter exceeds 5070 nm the quantum-size cascades are fully washed out, and we arrive at the mesoscopic regime. Below this regime the critical current density jc exhibits the quantum-size oscillations with pronounced resonant enhancements: the smaller the diameter, the more significant is the enhancement. Thickness fluctuations of real samples will smooth out such oscillations into an overall growth of jc with decreasing nanowire diameter. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000268617500092 |
Publication Date |
2009-07-22 |
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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 |
|
Series Issue |
|
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 |
21 |
Open Access |
|
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| |
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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| |
Call Number |
UA @ lucian @ c:irua:77949 |
Serial |
3358 |
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| Permanent link to this record |
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Author |
Chen, Y.; Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M. |
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Title |
Superconducting nanowires: quantum confinement and spatially dependent Hartree-Fock potential |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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| |
Volume |
21 |
Issue |
43 |
Pages |
435701,1-435701,7 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
It is well known that, in bulk, the solution of the Bogoliubovde Gennes equations is the same whether or not the HartreeFock term is included. Here the HartreeFock potential is position independent and so gives the same contribution to both the single-electron energies and the Fermi level (the chemical potential). Thus, the single-electron energies measured from the Fermi level (they control the solution) stay the same. This is not the case for nanostructured superconductors, where quantum confinement breaks the translational symmetry and results in a position-dependent HartreeFock potential. In this case its contribution to the single-electron energies depends on the relevant quantum numbers. We numerically solved the Bogoliubovde Gennes equations with the HartreeFock term for a clean superconducting nanocylinder and found a shift of the curve representing the thickness-dependent oscillations of the critical superconducting temperature to larger diameters. |
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| |
Address |
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| |
Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
000270642700012 |
Publication Date |
2009-10-09 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.649 |
Times cited |
12 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 2.649; 2009 IF: 1.964 |
|
| |
Call Number |
UA @ lucian @ c:irua:79162 |
Serial |
3360 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M. |
|
| |
Title |
Superconducting nanowires: quantum-confinement effect on the critical magnetic field and supercurrent |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
International journal of modern physics: B: condensed matter physics, statistical physics, applied physics
T2 – 32nd International Workshop on Condensed Matter Theories, Aug 12-19, 2008, Loughborough Univ, Loughborough, England |
Abbreviated Journal |
Int J Mod Phys B |
|
| |
Volume |
23 |
Issue |
20-21 |
Pages |
4257-4268 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
We study the effect of electron confinement on the superconducting-to-normal phase transition driven by a magnetic field and/or on the current-carrying state of the superconducting condensate in nanowires. Our investigation is based on a self-consistent numerical solution of the Bogoliubov-de Gennes equations. We show that in a parallel magnetic field and/or in the presence of supercurrent the transition from superconducting to normal phase occurs as a cascade of discontinuous jumps in the superconducting order parameter for diameters D < 10 divided by 15 nm at T = 0. The critical magnetic field exhibits quantum-size oscillations with pronounced resonant enhancements. |
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| |
Address |
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| |
Corporate Author |
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Thesis |
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|
| |
Publisher |
World scientific |
Place of Publication |
Singapore |
Editor |
|
|
| |
Language |
|
Wos |
000274525500026 |
Publication Date |
2009-09-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0217-9792;1793-6578; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
0.736 |
Times cited |
1 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 0.736; 2009 IF: 0.408 |
|
| |
Call Number |
UA @ lucian @ c:irua:95673 |
Serial |
3362 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Dong, H.M.; Qin, H.; Zhang, J.; Peeters, F.M.; Xu, W. |
|
| |
Title |
Terahertz absorption window in bilayer graphene |
Type |
H1 Book chapter |
| |
Year |
2009 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
247-248 |
|
| |
Keywords |
H1 Book chapter; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We present a detailed theoretical study of terahertz (THz) optical absorption in bilayer graphene. Considering an air/graphene/dielectric-wafer system, we find that there is an absorption window in the range 3 similar to 30 THz. Such an absorption window is induced by different transition energies required for inter- and intra-band optical absorption in the presence of the Pauli blockade effect. As a result, the position and width of this THz absorption window depend sensitively on temperature and carrier density of the system. These results are pertinent to the applications of recently developed graphene systems as novel optoelectronic devices such as THz photo-detectors. |
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| |
Address |
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| |
Corporate Author |
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Thesis |
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| |
Publisher |
Ieee |
Place of Publication |
New York, N.Y. |
Editor |
|
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| |
Language |
|
Wos |
|
Publication Date |
0000-00-00 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
978-1-4244-5416-7 |
Additional Links |
UA library record; WoS full record; |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ lucian @ c:irua:99225 |
Serial |
3506 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Verberck, B. |
|
| |
Title |
Theoretical phonon dispersions in monolayers and multilayers of hexagonal boron-nitride |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
|
| |
Volume |
246 |
Issue |
11/12 |
Pages |
2802-2805 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Starting from an empirical force constant model of valence interactions and calculating by Ewald's method the electrostatic force constants, we derive the dynamical matrix for a monolayer and for multilayer systems of hexagonal boron nitride (h-BN). Solution of the secular problem leads to the corresponding phonon dispersion relations. The interplay between valence forces and Coulomb forces is discussed. A comparison with previous results on graphene and graphene multilayers is made. Our spectra on the h-BN monolayer are rather similar to previous ab initio theory results. Comparison is also made with Raman and infrared experimental results. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
Berlin |
Editor |
|
|
| |
Language |
|
Wos |
000272904100091 |
Publication Date |
2009-11-12 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.674 |
Times cited |
10 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 1.674; 2009 IF: 1.150 |
|
| |
Call Number |
UA @ lucian @ c:irua:80673 |
Serial |
3609 |
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| Permanent link to this record |
| |
|
| |
|
Author |
Michel, K.H.; Verberck, B. |
|
| |
Title |
Theory of elastic and piezoelectric effects in two-dimensional hexagonal boron nitride |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
80 |
Issue |
22 |
Pages |
224301,1-224301,10 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Starting from an empirical force constant model of valence interactions and calculating by Ewalds method the ion-ion force constants, we derive the dynamical matrix for a monolayer crystal of hexagonal boron nitride (h-BN). The phonon dispersion relations are calculated. The interplay between valence and Coulomb forces is discussed. It is shown by analytical methods that the longitudinal and the transverse optical (LO and TO) phonon branches for in-plane motion are degenerate at the Γ point of the Brillouin zone. Away from Γ, the LO branch exhibits pronounced overbending. It is found that the nonanalytic Coulomb contribution to the dynamical matrix causes a linear increase of the LO branch with increasing wave vector starting at Γ. This effect is general for two-dimensional (2D) ionic crystals. Performing a long-wavelength expansion of the dynamical matrix, we use Borns perturbation method to calculate the elastic constants (tension coefficients). Since the crystal is noncentrosymmetric, internal displacements due to relative shifts between the two sublattices (B and N) contribute to the elastic constants. These internal displacements are responsible for piezoelectric and dielectric phenomena. The piezoelectric stress constant and the dielectric susceptibility of 2D h-BN are calculated. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
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| |
Language |
|
Wos |
000273228500045 |
Publication Date |
2009-12-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
96 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
|
| |
Call Number |
UA @ lucian @ c:irua:80576 |
Serial |
3616 |
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| Permanent link to this record |
| |
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| |
|
Author |
Magnus, W.; Brosens, F.; Sorée, B. |
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| |
Title |
Time dependent transport in 1D micro- and nanostructures: solving the Boltzmann and Wigner-Boltzmann equations |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
|
|
| |
Volume |
193 |
Issue |
1 |
Pages |
012004,1-012004,4 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems |
|
| |
Abstract |
For many decades the Boltzmann distribution function has been used to calculate the non-equilibrium properties of mobile particles undergoing the combined action of various scattering mechanisms and externally applied force fields. When the latter give rise to the occurrence of inhomogeneous potential profiles across the region through which the particles are moving, the numerical solution of the Boltzmann equation becomes a highly complicated task. In this work we highlight a particular algorithm that can be used to solve the time dependent Boltzmann equation as well as its quantum mechanical extension, the WignerBoltzmann equation. As an illustration, we show the calculated distribution function describing electrons propagating under the action of both a uniform and a pronouncedly non-uniform electric field. |
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| |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Bristol |
Editor |
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| |
Language |
|
Wos |
000277100400004 |
Publication Date |
2009-11-17 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1742-6596; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
2 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ lucian @ c:irua:82861 |
Serial |
3667 |
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| Permanent link to this record |
| |
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| |
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Author |
Karapetrov, G.; Milošević, M.V.; Iavarone, M.; Fedor, J.; Belkin, A.; Novosad, V.; Peeters, F.M. |
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| |
Title |
Transverse instabilities of multiple vortex chains in magnetically coupled NbSe2/permalloy superconductor/ferromagnet bilayers |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
80 |
Issue |
18 |
Pages |
180506,1-180506,4 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Using scanning tunneling microscopy and Ginzburg-Landau simulations, we explore vortex configurations in magnetically coupled NbSe2/permalloy superconductor/ferromagnet bilayer. The permalloy film with stripe domain structure induces periodic local magnetic induction in the superconductor, creating a series of pinning-antipinning channels for externally added magnetic flux quanta. Such laterally confined Abrikosov vortices form quasi-one-dimensional arrays (chains). The transitions between multichain states occur through propagation of kinks at the intermediate fields. At high fields we show that the system becomes nonlinear due to a change in both the number of vortices and the confining potential. The longitudinal instabilities of the resulting vortex structures lead to vortices levitating in the antipinning channels. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
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| |
Language |
|
Wos |
000272310900031 |
Publication Date |
2009-11-18 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
38 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
|
| |
Call Number |
UA @ lucian @ c:irua:80314 |
Serial |
3729 |
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| Permanent link to this record |
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| |
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Author |
Berdiyorov, G.R.; Milošević, M.V.; Peeters, F.M. |
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| |
Title |
Tunable kinematics of phase-slip lines in a superconducting stripe with magnetic dots |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
80 |
Issue |
21 |
Pages |
214509,1-214509,7 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Using numerical simulations, we study the dynamic properties of a superconducting stripe with a perpendicular magnetized ferromagnet on top in the presence of an applied dc current. In the resistive state conventional phase-slip lines are transformed into kinematic vortex-antivortex pairs with special dynamic behavior. In addition, the location of phase slippage in the sample is predetermined by the position of the magnetic dot. Both these effects directly influence the dynamics of the superconducting condensate and lead to periodic oscillations of the voltage across the sample with a frequency tunable both by the applied current and by the magnetization of the magnet. We found that the frequency of the voltage oscillations increases with increasing number of magnetic dots. |
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Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
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| |
Language |
|
Wos |
000273228200084 |
Publication Date |
2009-12-09 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
33 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
|
| |
Call Number |
UA @ lucian @ c:irua:80575 |
Serial |
3743 |
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| Permanent link to this record |
| |
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| |
|
Author |
Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M. |
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| |
Title |
Tuning the superconducting properties of nanomaterials |
Type |
H1 Book chapter |
| |
Year |
2009 |
Publication |
|
Abbreviated Journal |
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| |
Volume |
|
Issue |
|
Pages |
1-14 |
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| |
Keywords |
H1 Book chapter; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT) |
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| |
Abstract |
Electron continement and its effect on the superconducting-to-normal phase transition driven by a magentic field and/or a current is studied in nanowires. Our investigation is based on a self-consistent numerical solution of the Bogoliubov-de Gennes equations. We find that in a parallel magneitc field and/or in the presence of a supercurrent the transition from the superconducting to the normal phase occurs as a cascade of discontinuous jumps in the superconducting order parameter for diameters D < 10 divided by 15 nm at T = 0. The critical magentic field exhibits quantum-size oscillations with pronounced resonant enhancements as a function of the wire radius. |
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| |
Address |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
Dordrecht |
Editor |
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| |
Language |
|
Wos |
000274282900001 |
Publication Date |
2009-07-29 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
1874-6500; |
ISBN |
978-90-481-3118-1 |
Additional Links |
UA library record; WoS full record |
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| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
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| |
Call Number |
UA @ lucian @ c:irua:99226 |
Serial |
3761 |
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| Permanent link to this record |
| |
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| |
|
Author |
Masir, M.R.; Vasilopoulos, P.; Peeters, F.M. |
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| |
Title |
Tunneling, conductance, and wavevector filtering through magnetic barriers in bilayer graphene |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
79 |
Issue |
3 |
Pages |
035409,1-035409,8 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
We evaluate the transmission and conductance through magnetic barrier structures in bilayer graphene. In particular we consider a magnetic step, single and double barriers, -function barriers, as well as barrier structures that have average magnetic field equal to zero. The transmission depends strongly on the direction of the incident electron or hole wavevector and gives the possibility to construct a direction-dependent wavevector filter. The results contrast sharply with previous results on single-layer graphene. In general, the angular range of perfect transmission becomes drastically wider and the gaps narrower. This perfect transmission range decreases with the number of barriers, the barrier width, and the magnetic field. Depending on the structure, a variety of transmission resonances occur that are reflected in the conductance through the structure. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
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| |
Language |
|
Wos |
000262978200107 |
Publication Date |
2009-01-14 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
80 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
|
| |
Call Number |
UA @ lucian @ c:irua:75983 |
Serial |
3762 |
|
| Permanent link to this record |
| |
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| |
|
Author |
Pourghaderi, M.A.; Magnus, W.; Sorée, B.; Meuris, M.; de Meyer, K.; Heyns, M. |
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| |
Title |
Tunneling-lifetime model for metal-oxide-semiconductor structures |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
80 |
Issue |
8 |
Pages |
085315,1-085315,10 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
In this paper we investigate the basic physics of charge carriers (electrons) leaking out of the inversion layer of a metal-oxide-semiconductor capacitor with a biased gate. In particular, we treat the gate leakage current as resulting from two combined processes: (1) the time-dependent decay of electron wave packets representing the inversion-layer charge and (2) the local generation of new electrons replacing those that have leaked away. As a result, the gate current simply emerges as the ratio of the total charge in the inversion layer to the tunneling lifetime. The latter is extracted from the quantum dynamics of the decaying wave packets, while the generation rate is incorporated as a phenomenological source term in the continuity equation. Not only do the gate currents calculated with this model agree very well with experiment, the model also provides an onset to solve the paradox of the current-free bound states representing the resonances of the Schrödinger equation that governs the fully coupled metal-oxide-semiconductor system. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
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| |
Language |
|
Wos |
000269639300076 |
Publication Date |
2009-08-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
2 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
|
| |
Call Number |
UA @ lucian @ c:irua:78294 |
Serial |
3763 |
|
| Permanent link to this record |
| |
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| |
|
Author |
Lin, N.S.; Misko, V.R.; Peeters, F.M. |
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| |
Title |
Unconventional vortex dynamics in mesoscopic superconducting corbino disks |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
|
| |
Volume |
102 |
Issue |
19 |
Pages |
197003,1-197003,4 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The discrete shell structure of vortex matter strongly influences the flux dynamics in mesoscopic superconducting Corbino disks. While the dynamical behavior is well understood in large and in very small disks, in the intermediate-size regime it occurs to be much more complex and unusual, due to (in)commensurability between the vortex shells. We demonstrate unconventional vortex dynamics (inversion of shell velocities with respect to the gradient driving force) and angular melting (propagating from the boundary where the shear stress is minimum, towards the center) in mesoscopic Corbino disks. |
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| |
Address |
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| |
Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000266207700063 |
Publication Date |
2009-05-14 |
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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 |
0031-9007;1079-7114; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
8.462 |
Times cited |
18 |
Open Access |
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| |
Notes |
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Approved |
Most recent IF: 8.462; 2009 IF: 7.328 |
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| |
Call Number |
UA @ lucian @ c:irua:77396 |
Serial |
3800 |
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| Permanent link to this record |
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Author |
Pereira, J.M.; Peeters, F.M.; Costa Filho, R.N.; Farias, G.A. |
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| |
Title |
Valley polarization due to trigonal warping on tunneling electrons in graphene |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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| |
Volume |
21 |
Issue |
4 |
Pages |
045301,1-045301,4 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The effect of trigonal warping on the transmission of electrons tunneling through potential barriers in graphene is investigated. We present calculations of the transmission coefficient for single and double barriers as a function of energy, incidence angle and barrier heights. The results show remarkable valley-dependent directional effects for barriers oriented parallel to the armchair or parallel to the zigzag direction. These results indicate that electrostatic gates can be used as valley filters in graphene-based devices. |
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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 |
London |
Editor |
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Language |
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Wos |
000262354700004 |
Publication Date |
2008-12-20 |
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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 |
0953-8984;1361-648X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
2.649 |
Times cited |
78 |
Open Access |
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| |
Notes |
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Approved |
Most recent IF: 2.649; 2009 IF: 1.964 |
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| |
Call Number |
UA @ lucian @ c:irua:75736 |
Serial |
3834 |
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| Permanent link to this record |
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Author |
Szafran, B.; Poniedziałek, M.R.; Peeters, F.M. |
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Title |
Violation of Onsager symmetry for a ballistic channel Coulomb coupled to a quantum ring |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Europhysics letters |
Abbreviated Journal |
Epl-Europhys Lett |
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| |
Volume |
87 |
Issue |
4 |
Pages |
47002,1-47002,6 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate a scattering of electron which is injected individually into an empty ballistic channel containing a cavity that is Coulomb coupled to a quantum ring charged with a single electron. We solve the time-dependent Schrödinger equation for the electron pair with an exact account for the electron-electron correlation. Absorption of energy and angular momentum by the quantum ring is not an even function of the external magnetic field. As a consequence we find that the electron backscattering probability is asymmetric in the magnetic field and thus violates Onsager symmetry. |
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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 |
Paris |
Editor |
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Language |
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Wos |
000270146400017 |
Publication Date |
2009-09-02 |
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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 |
0295-5075;1286-4854; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
1.957 |
Times cited |
4 |
Open Access |
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| |
Notes |
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Approved |
Most recent IF: 1.957; 2009 IF: 2.893 |
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| |
Call Number |
UA @ lucian @ c:irua:79734 |
Serial |
3847 |
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| Permanent link to this record |
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Author |
Bending, S.J.; Neal, J.S.; Milošević, M.V.; Potenza, A.; san Emeterio, L.; Marrows, C.H. |
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Title |
Vortex-antivortex 'molecular crystals' in hybrid ferromagnet/superconductor structures |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
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| |
Volume |
150 |
Issue |
5 |
Pages |
052019 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We have used high resolution Hall probe microscopy to image vortex-antivortex (V-AV) 'molecules' induced in superconducting Pb films by the stray fields from square arrays of ferromagnetic Co/Pt dots. We have directly observed spontaneous V-AV pairs and studied how they interact with added 'free' (anti)fluxons in an applied magnetic field. We observe a rich variety of subtle phenomena arising from competing symmetries in our system which can either drive added antivortices to join AV shells around nanomagnets or stabilise the translationally symmetric AV lattice between the dots. Added vortices annihilate AV shells, leading eventually to a stable 'nulling' state with no free fluxons, which should exhibit a strongly (field-)enhanced critical current. At higher densities we actually observe vortex shells around the magnets, stabilised by the asymmetric anti-pinning potential. Our experimental findings are in good agreement with Ginzburg-Landau calculations. |
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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 |
Bristol |
Editor |
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Language |
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Wos |
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Publication Date |
2009-04-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1742-6588;1742-6596; |
ISBN |
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Additional Links |
UA library record |
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Impact Factor |
|
Times cited |
|
Open Access |
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| |
Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:106136 |
Serial |
3855 |
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| Permanent link to this record |
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Author |
Xu, B.; Milošević, M.V.; Peeters, F.M. |
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Title |
Vortex matter in oblate mesoscopic superconductors with a hole: broken symmetry vortex states and multi-vortex entry |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
New journal of physics |
Abbreviated Journal |
New J Phys |
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| |
Volume |
11 |
Issue |
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Pages |
013020,1-013020,21 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using three-dimensional (3D) numerical discretization of the GinzburgLandau (GL) equations, we investigate the superconducting state of a sphere with a piercing hole in the presence of a magnetic field. In the case of samples with central perforation, in axially applied homogeneous magnetic field, we realized unconventional vortex states of broken symmetry due to complex, 3D competing interactions, which depend on the GL parameter ê. For certain sizes of the sample, non-hysteretic multi-vortex entry and exit is predicted with the non-existence of some vorticities as stable states. In a tilted magnetic field, we studied the gradual transformation of 3D flux patterns into 1D vortex chains, where vortices align along the perforation, and the evolvement of the multi-vortex entry as well. We analyze the flux-guiding ability of the hole in a tilted field, which leads to fractional flux response in magnetization M(H) curves. |
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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 |
Bristol |
Editor |
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Language |
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Wos |
000262932500003 |
Publication Date |
2009-01-17 |
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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 |
1367-2630; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.786 |
Times cited |
8 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.786; 2009 IF: 3.312 |
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Call Number |
UA @ lucian @ c:irua:75986 |
Serial |
3873 |
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| Permanent link to this record |
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Author |
Connolly, M.R.; Milošević, M.V.; Bending, S.J.; Clem, J.R.; Tamegai, T. |
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Title |
Vortex 'puddles' and magic vortex numbers in mesoscopic superconducting disks |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
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| |
Volume |
150 |
Issue |
5 |
Pages |
052039 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The magnetic properties of a superconducting disk change dramatically when its dimensions become mesoscopic. Unlike large disks, where the screening currents induced by an applied magnetic field are strong enough to force vortices to accumulate in a 'puddle' at the centre, in a mesoscopic disk the interaction between one of these vortices and the edge currents can be comparable to the intervortex repulsion, resulting in a destruction of the ordered triangular vortex lattice structure at the centre. Vortices instead form clusters which adopt polygonal and shell-like structures which exhibit magic number states similar to those of charged particles in a confining potential, and electrons in artificial atoms. We have fabricated mesoscopic high temperature superconducting Bi2Sr2CaCu2O8+δ disks and investigated their magnetic properties using magneto-optical imaging (MOI) and high resolution scanning Hall probe microscopy (SHPM). The temperature dependence of the vortex penetration field measured using MOI is in excellent agreement with models of the thermal excitation of pancake vortices over edge barriers. The growth of the central vortex puddle has been directly imaged using SHPM and magic vortex numbers showing higher stability have been correlated with abrupt jumps in the measured local magnetisation curves. |
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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 |
Bristol |
Editor |
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Language |
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Wos |
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Publication Date |
2009-04-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1742-6588;1742-6596; |
ISBN |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
|
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:106137 |
Serial |
3881 |
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| Permanent link to this record |
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Author |
Leenaerts, O.; Partoens, B.; Peeters, F.M. |
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Title |
Water on graphene: hydrophobicity and dipole moment using density functional theory |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
79 |
Issue |
23 |
Pages |
235440,1-235440,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We apply density-functional theory to study the adsorption of water clusters on the surface of a graphene sheet and find i) graphene is highly hydrophobic and ii) adsorbed water has very little effect on the electronic structure of graphene. A single water cluster on graphene has a very small average dipole moment which is in contrast with an ice layer that exhibits a strong dipole moment. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000267699500147 |
Publication Date |
2009-06-29 |
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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 |
292 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:77693 |
Serial |
3904 |
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| Permanent link to this record |
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Author |
Chaves, A.; Farias, G.A.; Peeters, F.M.; Szafran, B. |
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Title |
Wave packet dynamics in semiconductor quantum rings of finite width |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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Volume |
80 |
Issue |
12 |
Pages |
125331,1-125331,14 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The time evolution of a wave packet injected into a semiconductor quantum ring is investigated in order to obtain the transmission and reflection probabilities. Within the effective-mass approximation, the time-dependent Schrödinger equation is solved for a system with nonzero width of the ring and leads and finite potential-barrier heights, where we include smooth lead-ring connections. In the absence of a magnetic field, an analysis of the projection of the wave function over the different subband states shows that when the injected wave packet is within a single subband, the junction can scatter this wave packet into different subbands but remarkably at the second junction the wave packet is scattered back into the subband state of the incoming wave packet. If a magnetic field is applied perpendicularly to the ring plane, transmission and reflection probabilities exhibit Aharonov-Bohm (AB) oscillations and the outgoing electrons may end up in different subband states from those of the incoming electrons. Localized impurities, placed in the ring arms, influence the AB oscillation period and amplitude. For a single impurity or potential barrier of sufficiently strong strength, the period of the AB oscillations is halved while for two impurities localized in diametrically opposite points of the ring, the original AB period is recovered. A theoretical investigation of the confined states and time evolution of wave packets in T wires is also made, where a comparison between this system and the lead-ring junction is drawn. |
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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 |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000270383300098 |
Publication Date |
2009-09-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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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 |
40 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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| |
Call Number |
UA @ lucian @ c:irua:79231 |
Serial |
3906 |
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| Permanent link to this record |
