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Author Croitoru, M.D.; Zachmann, M.; Vagov, A.; Axt, V.M.; Shanenko, A.A.; Kettmann, P.; Papenkort, T.; Kuhn, T.
Title Coherent dynamics of confinement-induced multiband superconductors Type A1 Journal article
Year 2014 Publication Physica: C : superconductivity Abbreviated Journal Physica C
Volume 503 Issue (up) Pages 183-186
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the coherent dynamics of pairing in a nanoscale superconductor, that is intrinsically multiband, after an external perturbation in the non-adiabatic regime. The description of the dynamics of the pairing order is within the density-matrix approach based on the BCS model and the Bogoliubov-de Gennes equations. We find that for certain resonant wire widths the superconducting order parameter exhibits two oscillatory frequencies which are determined by the long-time asymptotic values of the subgaps. This in turn leads to a pronounced beating phenomenon. (C) 2014 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000340070600040 Publication Date 2014-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4534; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.404 Times cited 1 Open Access
Notes ; M.D.C. acknowledges the support from the Back to Belgium Grant of the federal Science Policy (BELSPO). ; Approved Most recent IF: 1.404; 2014 IF: 0.942
Call Number UA @ lucian @ c:irua:118745 Serial 378
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Author Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M.
Title Dependence of superconducting properties on the size and shape of a nanoscale superconductor: from nanowire to film Type A1 Journal article
Year 2007 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 76 Issue (up) Pages 024511,1-6
Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000248496200104 Publication Date 2007-07-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 54 Open Access
Notes Fwo-Vi; Iap; Bof-Top Approved Most recent IF: 3.836; 2007 IF: 3.172
Call Number UA @ lucian @ c:irua:69655 Serial 643
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Author Shanenko, A.A.; Tempère, J.; Brosens, F.; Devreese, J.T.
Title Mesoscopic samples: the superconducting condensate via the Gross.Pitaevskii scenario Type A1 Journal article
Year 2004 Publication Solid state communications Abbreviated Journal Solid State Commun
Volume 131 Issue (up) Pages 409-414
Keywords A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000223011700012 Publication Date 2004-03-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1098; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.554 Times cited 1 Open Access
Notes Approved Most recent IF: 1.554; 2004 IF: 1.523
Call Number UA @ lucian @ c:irua:48282 Serial 2000
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Author Shanenko, A.A.; Vagov, A.; Peeters, F.M.; Aguiar, J.A.
Title Nanofilms as effectively multiband superconductors: Intraband-pairing approximation and Ginzburg-Landau theory Type A1 Journal article
Year 2014 Publication Physica: B : condensed matter Abbreviated Journal Physica B
Volume 455 Issue (up) Pages 3-5
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract It is well-known that the Ginzburg-Landau (GL) theory is a reliable and powerful theoretical tool to investigate the magnetic response of a superconducting state. However, in its standard form, this approach is not applicable to atomically uniform nano-thin superconducting films which are effective multiband superconductors. Here we discuss a relevant generalization of the GL theory, focusing on the underlying intraband-pairing approximation. (C) 2014 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000344239200002 Publication Date 2014-07-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.386 Times cited 1 Open Access
Notes ; This work was supported by the “Odysseus” Program of the Flemish Government, the Flemish Science Foundation (FWO-VI), and the Methusalem program. A.A.S. acknowledges the support of the Brazilian agencies CNPq and FACEPE (APQ-0589-1.05/08). ; Approved Most recent IF: 1.386; 2014 IF: 1.319
Call Number UA @ lucian @ c:irua:121192 Serial 2256
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Author Shanenko, A.A.; Croitoru, M.D.; Mints, R.G.; Peeters, F.M.
Title New Andreev-type states in superconducting nanowires Type A1 Journal article
Year 2007 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 99 Issue (up) Pages 067007,1-4
Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000248664700056 Publication Date 2007-08-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 30 Open Access
Notes Fwo -Vi; Bof-Top; Iap Approved Most recent IF: 8.462; 2007 IF: 6.944
Call Number UA @ lucian @ c:irua:69664 Serial 2304
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Author Shanenko, A.A.; Smondyrev, M.A.; Devreese, J.T.
Title Stabilisation of bipolarons by polaron environment Type A1 Journal article
Year 1996 Publication Solid state communications Abbreviated Journal Solid State Commun
Volume 98 Issue (up) Pages 1091
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos A1996UT02900012 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1098 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.897 Times cited 11 Open Access
Notes Approved PHYSICS, APPLIED 28/145 Q1 #
Call Number UA @ lucian @ c:irua:16186 Serial 3115
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Author Smondyrev, M.A.; Shanenko, A.A.; Devreese, J.T.
Title Stability criterion for large bipolarons in a polaron-gas background Type A1 Journal article
Year 2001 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 63 Issue (up) Pages 024302,1-4
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121; 0163-1829 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited Open Access
Notes Approved Most recent IF: 3.836; 2001 IF: NA
Call Number UA @ lucian @ c:irua:34310 Serial 3122
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Author Shanenko, A.A.; Croitoru, M.D.; Vagov, A.; Peeters, F.M.
Title Superconducting nanowires : new type of BCS-BEC crossover driven by quantum-size effects Type P1 Proceeding
Year 2011 Publication Abbreviated Journal
Volume Issue (up) Pages 119-127
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract We show that a superconducting quantum nanowire undergoes a new type of BCS-BEC crossover each time when an electron subband approaches the Fermi surface. In this case the longitudinal Cooper-pair size drops by two-three orders of magnitude down to a few nanometers. This unconventional BCS-BEC crossover is driven by quantum-size effects rather than by tuning the fermion-fermion interaction.
Address
Corporate Author Thesis
Publisher Springer Place of Publication Dordrecht Editor
Language Wos 000289872900009 Publication Date 2010-12-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1874-6500;1874-6535; ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP) and the ESF-network: INSTANS. M.D.C. acknowledges support from the Alexander von Humboldt Foundation. ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:89946 Serial 3359
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Author Shanenko, A.A.; Croitoru, M.D.; Peeters, F.M.
Title Superconductivity in the quantum-size regime Type P1 Proceeding
Year 2008 Publication Abbreviated Journal
Volume Issue (up) Pages 79-103
Keywords P1 Proceeding; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Abstract Recent technological advances resulted in high-quality superconducting metallic nanofilms and nanowires. The physical properties of such nanostructures are governed by the size-quantization of the transverse electron spectrum. This has a substantial impact on the basic superconducting characteristics, e.g., the order parameter, the critical temperature and the critical magnetic field. In the present paper we give an overview of our theoretical results on this subject. Based on a numerical self-consistent solution of the Bogoliubov-de Gennes equations, we investigate how the superconducting properties are modified in the quantum-size regime.
Address
Corporate Author Thesis
Publisher Place of Publication S.l. Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-4020-9144-5 ISBN 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:75944 Serial 3374
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Author Komendová, L.; Shanenko, A.A.; Milošević, M.V.; Peeters, F.M.
Title The healing lengths in two-band superconductors in extended Ginzburg-Landau theory Type A1 Journal article
Year 2012 Publication Physica: C : superconductivity Abbreviated Journal Physica C
Volume 479 Issue (up) Pages 126-129
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the vortex profiles in two-gap superconductors using the extended Ginzburg-Landau theory. The results shed more light on the disparity between the effective length scales in two bands. We compare the behavior expected from the standard Ginzburg-Landau theory with this new approach, and find good qualitative agreement in the case of LiFeAs. (C) 2011 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000308580600029 Publication Date 2012-01-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4534; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.404 Times cited 1 Open Access
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: 1.404; 2012 IF: 0.718
Call Number UA @ lucian @ c:irua:101871 Serial 3585
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Author Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M.
Title Superconducting nanowires: quantum-confinement effect on the critical magnetic field and supercurrent Type P1 Proceeding
Year 2010 Publication Abbreviated Journal
Volume Issue (up) Pages 327-338
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
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 held exhibits quantum-size oscillations with pronounced resonant enhancements.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000278418300025 Publication Date 2010-04-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), Interuni-versity Attraction Poles Programme -Belgian State -Belgian Science Policy (IAP) and the ESF-AQDJJ network. ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:83294 Serial 3361
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Author Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M.
Title Tuning the superconducting properties of nanomaterials Type H1 Book chapter
Year 2009 Publication Abbreviated Journal
Volume Issue (up) Pages 1-14
Keywords H1 Book chapter; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
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.
Address
Corporate Author Thesis
Publisher Springer Place of Publication Dordrecht Editor
Language Wos 000274282900001 Publication Date 2009-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1874-6500; ISBN 978-90-481-3118-1 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:99226 Serial 3761
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Author Vagov, A.V.; Shanenko, A.A.; Milošević, M.V.; Axt, V.M.; Peeters, F.M.
Title Extended Ginzburg-Landau formalism : systematic expansion in small deviation from the critical temperature Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue (up) 1 Pages 014502-014502,17
Keywords A1 Journal article; Condensed Matter Theory (CMT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000298985100002 Publication Date 2012-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 36 Open Access
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
Call Number UA @ lucian @ c:irua:96232 Serial 1155
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Author Shanenko, A.A.; Croitoru, M.D.; Peeters, F.M.
Title Oscillations of the superconducting temperature induced by quantum well states in thin metallic films: numerical solution of the Bogoliubov-de Gennes equations Type A1 Journal article
Year 2007 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 75 Issue (up) 1 Pages 014519,1-9
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000243894600126 Publication Date 2007-01-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 85 Open Access
Notes Fwo-Vi; Bof-Top; Iap Approved Most recent IF: 3.836; 2007 IF: 3.172
Call Number UA @ lucian @ c:irua:63749 Serial 2535
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Author Shanenko, A.A.; Croitoru, M.D.
Title Shape resonances in the superconducting order parameter of ultrathin nanowires Type A1 Journal article
Year 2006 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 73 Issue (up) 1 Pages 012510,1-4
Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000235009000033 Publication Date 2006-01-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 41 Open Access
Notes Approved Most recent IF: 3.836; 2006 IF: 3.107
Call Number UA @ lucian @ c:irua:56613 Serial 2990
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Author Shanenko, A.A.; Croitoru, M.D.; Vagov, A.; Peeters, F.M.
Title Giant drop in the Bardeen-Cooper-Schrieffer coherence length induced by quantum size effects in superconducting nanowires Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue (up) 10 Pages 104524-104524,6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The BCS coherence length in low-dimensional superconductors is dramatically modified by quantum-size effects. In particular, for nanowires made of conventional superconducting materials, we show that the longitudinal zero-temperature coherence length exhibits width-dependent drops by 23 orders of magnitude each time when the bottom of one of single-electron subbands formed due to the transverse quantization of electron motion is situated in a close vicinity to the Fermi level. This phenomenon has strong similarities to the well-known BCS-BEC (Bose-Einstein condensation) crossover in ultracold fermionic condensates but with an important exception: it is driven by the transverse quantization of the electron motion rather than by the externally controlled strength of the fermion-fermion interaction.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282269600005 Publication Date 2010-09-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 29 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF-network: INSTANS. M. D. C. acknowledges support from the Alexander von Humboldt Foundation. A. A. S. thanks R. G. Mints, W. V. Pogosov, D. Y. Vodolazov, A. Perali, and A. Bianconi for fruitful discussions. ; Approved Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85419 Serial 1337
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Author Croitoru, M.D.; Vagov, A.; Shanenko, A.A.; Axt, V.M.
Title The Cooper problem in nanoscale : enhancement of the coupling due to confinement Type A1 Journal article
Year 2012 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 25 Issue (up) 12 Pages 124001-124005
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In 1956 Cooper demonstrated (1956 Phys. Rev. 104 1189) that, no matter how weak the attraction is, two electrons in three-dimensional (3D) space just above the Fermi sea could be bound. In this work we investigate the influence of confinement on the binding energy of a Cooper pair. We show that confinement-induced modification of the Fermi sea results in a significant increase of the binding energy, when the bottom of an energy subband is very close to the Fermi surface.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000311418100004 Publication Date 2012-11-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.878 Times cited 9 Open Access
Notes ; MDC acknowledges support by the European Community under the Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR). ; Approved Most recent IF: 2.878; 2012 IF: 2.758
Call Number UA @ lucian @ c:irua:105121 Serial 3573
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Author Orlova, N.V.; Shanenko, A.A.; Milošević, M.V.; Peeters, F.M.; Vagov, A.V.; Axt, V.M.
Title Ginzburg-Landau theory for multiband superconductors : microscopic derivation Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue (up) 13 Pages 134510-134518
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A procedure to derive the Ginzburg-Landau (GL) theory from the multiband BCS Hamiltonian is developed in a general case with an arbitrary number of bands and arbitrary interaction matrix. It combines the standard Gor'kov truncation and a subsequent reconstruction in order to match accuracies of the obtained terms. This reconstruction recovers the phenomenological GL theory as obtained from the Landau model of phase transitions but offers explicit microscopic expressions for the relevant parameters. Detailed calculations are presented for a three-band system treated as a prototype multiband superconductor. It is demonstrated that the symmetry in the coupling matrix may lead to the chiral ground state with the phase frustration, typical for systems with broken time-reversal symmetry. DOI: 10.1103/PhysRevB.87.134510
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000317586700002 Publication Date 2013-04-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 57 Open Access
Notes ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). A.A.S. acknowledges useful discussions with D. Neilson. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108464 Serial 1344
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Author Chen, Y.; Shanenko, A.A.; Peeters, F.M.
Title Hollow nanocylinder: multisubband superconductivity induced by quantum confinement Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue (up) 13 Pages 134523-134523:11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Quantization of the transverse electron motion in high-quality superconducting metallic nanowires and nanofilms results in the formation of well-distinguished single-electron subbands. They shift in energy with changing thickness, which is known to cause quantum-size superconducting oscillations. The formation of multiple subbands results in a multigap structure induced by the interplay between quantum confinement and Andreev mechanism. We investigate multisubband superconductivity in a hollow nanocylinder by numerically solving the Bogoliubov-de Gennes equations. When changing the inner radius and thickness of the hollow nanocylinder, we find a crossover from an irregular pattern of quantum-size superconducting oscillations, typical of nanowires, to an almost regular regime, specific for superconducting nanofilms. At this crossover the multigap structure becomes degenerate. The ratio of the critical temperature to the energy gap increases and approaches its bulk value while being reduced by 20-30% due to Andreev-type states driven by quantum confinement in the irregular regime.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000277207900098 Publication Date 2010-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 21 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-VI), the Interuniversity Attraction Poles Programme, Belgian States, Belgian Science Policy (IAP) and the ESF-AQDJJ network. ; Approved Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:95623 Serial 1481
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Author Vagov, A.; Shanenko, A.A.; Milošević, M.V.; Axt, V.M.; Peeters, F.M.
Title Two-band superconductors : extended Ginzburg-Landau formalism by a systematic expansion in small deviation from the critical temperature Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue (up) 14 Pages 144514
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We derive the extended Ginzburg-Landau (GL) formalism for a clean s-wave two-band superconductor by employing a systematic expansion of the free-energy functional and the corresponding matrix gap equation in powers of the small deviation from the critical temperature tau = 1 – T/T-c. The two lowest orders of this expansion produce the equation for T-c and the standard GL theory. It is shown that in agreement with previous studies, this two-band GL theory maps onto the single-band GL model and thus fails to describe the difference in the spatial profiles of the two-band condensates. We prove that this difference appears already in the leading correction to the standard GL theory, which constitutes the extended GL formalism. We derive linear differential equations that determine the leading corrections to the band order parameters and magnetic field, discuss the validity of these equations, and consider examples of an important interplay between the band condensates. Finally, we present numerical results for the thermodynamic critical magnetic field and temperature-dependent band gaps for recent materials of interest, which are in very good agreement with those obtained from the full BCS approach in a wide temperature range. To this end, we emphasize the advantages of our extended GL theory in comparison with the often used two-component GL-like model based on an unreconstructed two-band generalization of the Gor'kov derivation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000309776800001 Publication Date 2012-10-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 44 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). Authors are indebted to Y. Singh and R. Prozorov for discussions and for providing recent experimental data. A. V. is grateful to W. Pesch for stimulating discussions and critical comments on this work. ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101798 Serial 3769
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Author Chen, Y.; Shanenko, A.A.; Perali, A.; Peeters, F.M.
Title Superconducting nanofilms : molecule-like pairing induced by quantum confinement Type A1 Journal article
Year 2012 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 24 Issue (up) 18 Pages 185701-185701,8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Quantum confinement of the perpendicular motion of electrons in single-crystalline metallic superconducting nanofilms splits the conduction band into a series of single-electron subbands. A distinctive feature of such a nanoscale multi-band superconductor is that the energetic position of each subband can vary significantly with changing nanofilm thickness, substrate material, protective cover and other details of the fabrication process. It can occur that the bottom of one of the available subbands is situated in the vicinity of the Fermi level. We demonstrate that the character of the superconducting pairing in such a subband changes dramatically and exhibits a clear molecule-like trend, which is very similar to the well-known crossover from the Bardeen-Cooper-Schrieffer regime to Bose-Einstein condensation (BCS-BEC) observed in trapped ultracold fermions. For Pb nanofilms with thicknesses of 4 and 5 monolayers (MLs) this will lead to a spectacular scenario: up to half of all the Cooper pairs nearly collapse, shrinking in the lateral size (parallel to the nanofilm) down to a few nanometers. As a result, the superconducting condensate will be a coherent mixture of almost molecule-like fermionic pairs with ordinary, extended Cooper pairs.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000303500900018 Publication Date 2012-04-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984;1361-648X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.649 Times cited 26 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). AAS thanks A Bianconi, M D Croitoru and A V Vagov for useful discussions. AAS acknowledges the hospitality and fruitful interactions with G C Strinati, P Pieri and D Neilson during his visit to the University of Camerino, supported by the School of Advanced Studies of the University of Camerino. ; Approved Most recent IF: 2.649; 2012 IF: 2.355
Call Number UA @ lucian @ c:irua:98223 Serial 3357
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Author Shanenko, A.A.; Croitoru, M.D.; Peeters, F.M.
Title Magnetic-field induced quantum-size cascades in superconducting nanowires Type A1 Journal article
Year 2008 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 78 Issue (up) 2 Pages 024505,1-9
Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000258190200105 Publication Date 2008-07-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 42 Open Access
Notes Approved Most recent IF: 3.836; 2008 IF: 3.322
Call Number UA @ lucian @ c:irua:70559 Serial 1876
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Author Shanenko, A.A.; Orlova, N.V.; Vagov, A.; Milošević, M.V.; Axt, V.M.; Peeters, F.M.
Title Nanofilms as quantum-engineered multiband superconductors : the Ginzburg-Landau theory Type A1 Journal article
Year 2013 Publication Europhysics letters Abbreviated Journal Epl-Europhys Lett
Volume 102 Issue (up) 2 Pages 27003-27006
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Recently fabricated single-crystalline atomically flat metallic nanofilms are in fact quantum-engineered multiband superconductors. Here the multiband structure is dictated by the nanofilm thickness through the size quantization of the electron motion perpendicular to the nanofilm. This opens the unique possibility to explore superconductivity in well-controlled multi-band systems. However, a serious obstacle is the absence of a convenient and manageable theoretical tool to access new physical phenomena in such quasi-two-dimensional systems, including interplay of quantum confinement and fluctuations. Here we cover this gap and construct the appropriate multiband Ginzburg-Landau functional for nano-thin superconductors. Copyright (C) EPLA, 2013
Address
Corporate Author Thesis
Publisher Place of Publication Paris Editor
Language Wos 000319617700019 Publication Date 2013-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0295-5075;1286-4854; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.957 Times cited 8 Open Access
Notes ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 1.957; 2013 IF: 2.269
Call Number UA @ lucian @ c:irua:109859 Serial 2257
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Author Croitoru, M.D.; Shanenko, A.A.; Kaun, C.C.; Peeters, F.M.
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
Volume 80 Issue (up) 2 Pages 024513,1-024513,11
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000268617500092 Publication Date 2009-07-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 21 Open Access
Notes Approved Most recent IF: 3.836; 2009 IF: 3.475
Call Number UA @ lucian @ c:irua:77949 Serial 3358
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Author Komendová, L.; Chen, Y.; Shanenko, A.A.; Milošević, M.V.; Peeters, F.M.
Title Two-band superconductors : hidden criticality deep in the superconducting state Type A1 Journal article
Year 2012 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 108 Issue (up) 20 Pages 207002-207002,5
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We show that two-band superconductors harbor hidden criticality deep in the superconducting state, stemming from the critical temperature of the weaker band taken as an independent system. For sufficiently small interband coupling gamma the coherence length of the weaker band exhibits a remarkable deviation from the conventional monotonic increase with temperature, namely, a pronounced peak close to the hidden critical point. The magnitude of the peak scales as proportional to gamma(-mu), with the Landau critical exponent mu = 1/3, the same as found for the mean-field critical behavior with respect to the source field in ferromagnets and ferroelectrics. Here reported hidden criticality of multiband superconductors can be experimentally observed by, e.g., imaging of the variations of the vortex core in a broader temperature range. Similar effects are expected for the superconducting multilayers.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000304064000017 Publication Date 2012-05-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 75 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). Useful discussions with A. V. Vagov are acknowledged. ; Approved Most recent IF: 8.462; 2012 IF: 7.943
Call Number UA @ lucian @ c:irua:98945 Serial 3770
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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 (up) 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.
Address
Corporate Author Thesis
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
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Author Croitoru, M.D.; Shanenko, A.A.; Kaun, C.C.; Peeters, F.M.
Title Metallic nanograins : spatially nonuniform pairing induced by quantum confinement Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 83 Issue (up) 21 Pages 214509-214509,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract It is well known that the formation of discrete electron levels strongly influences the pairing in metallic nanograins. Here, we focus on another effect of quantum confinement in superconducting grains that was not studied previously, i.e., spatially nonuniform pairing. This effect is very significant when single-electron levels form bunches and/or a kind of shell structure. We find that, in highly symmetric grains, the order parameter can exhibit variations with position by an order of magnitude. Nonuniform pairing is closely related to a quantum-confinement-induced modification of the pairing-interaction matrix elements and size-dependent pinning of the chemical potential to groups of degenerate or nearly degenerate levels. For illustrative purposes, we consider spherical metallic nanograins and also rectangular shapes. We show that the relevant matrix elements are, as a rule, enhanced in the presence of quantum confinement, which favors spatial variations of the order parameter, compensating the corresponding energy cost. The size-dependent pinning of the chemical potential further increases the spatial variation of the pair condensate. The role of nonuniform pairing is smaller in less symmetric confining geometries and/or in the presence of disorder. However, it always remains of importance when the energy spacing between discrete electron levels δ is approaching the scale of the bulk gap ΔB, i.e., δ>0.10.2 ΔB.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000291310000006 Publication Date 2011-06-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 23 Open Access
Notes ; This work was supported by the Alexander von Humboldt Foundation, the Flemish Science Foundation (FWO-VI), and the Belgian Science Policy (IAP). M. D. C. acknowledges support of the European Community under a Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR). ; Approved Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:90081 Serial 2010
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Author Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M.; Axt, V.M.
Title Parity-fluctuation induced enlargement of the ratio \DeltaE/kBTc in metallic grains Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue (up) 21 Pages 214518-214518,12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000298114100003 Publication Date 2011-12-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 14 Open Access
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
Call Number UA @ lucian @ c:irua:94373 Serial 2555
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Author Chen, Y.; Shanenko, A.A.; Peeters, F.M.
Title Superconducting transition temperature of Pb nanofilms : impact of thickness-dependent oscillations of the phonon-mediated electron-electron coupling Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue (up) 22 Pages 224517-224517,6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract To date, several experimental groups reported measurements of the thickness dependence of T-c of atomically uniform single-crystalline Pb nanofilms. The reported amplitude of the T-c oscillations varies significantly from one experiment to another. Here we propose that the reason for this unresolved issue is an interplay of the quantum-size variations in the single-electron density of states with thickness-dependent oscillations in the phonon-mediated electron-electron coupling. Such oscillations in the coupling depend on the substrate material, the quality of the interface, the protection cover, and other details of the fabrication process, changing from one experiment to another. This explains why the available data do not exhibit one-voice consistency about the amplitude of the T-c oscillations. Our analyses are based on a numerical solution of the Bogoliubov-de Gennes equations for a superconducting slab.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000305251300006 Publication Date 2012-06-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 24 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:99076 Serial 3368
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Author Chen, Y.; Shanenko, A.A.; Croitoru, M.D.; Peeters, F.M.
Title Quantum cascades in nano-engineered superconductors : geometrical, thermal and paramagnetic effects Type A1 Journal article
Year 2012 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 24 Issue (up) 26 Pages 265702
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The effect of a parallel magnetic field on the orbital motion of electrons in high-quality superconducting nanowires resulting in a superconductor-to-normal transition which occurs through a cascade of jumps in the order parameter as a function of the magnetic field. Such cascades originate from the transverse size quantization that splits the conduction band into a series of subbands. Here, based on a numerical solution of the Bogoliubov-de Gennes equations for a hollow nanocylinder, we investigate how the quantum-size cascades depend on the confining geometry, i.e., by changing the cylinder radius R and its thickness d we cover the range from the nanowire-like to the nanofilm-like regime. The cascades are shown to become much less pronounced when increasing R/d, i.e., when the nanofilm-like regime is approached. When the temperature is non-zero they are thermally smoothed. This includes the spin-magnetic-field interaction which reduces the critical (depairing) parallel magnetic field H-c,H-parallel to but does not have any qualitative effect on the quantum cascades. From our calculations it is seen that the paramagnetic limiting field H-par significantly exceeds H-c,H-parallel to even in extremely narrow nanocylinders, i.e., when R, d are down to a few nanometers, and H-c,H-parallel to is only about 10% larger when switching-off the spin-magnetic-field interaction in this case. Both characteristic fields, H-c,H-parallel to and H-par, exhibit pronounced quantum-size oscillations. We demonstrate that the quantum cascades and the quantum-size oscillations survive in the presence of surface roughness.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000305640800014 Publication Date 2012-06-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984;1361-648X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.649 Times cited 6 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-VI) and the ESF-AQDJJ network. MDC acknowledges the support of the EU Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR). ; Approved Most recent IF: 2.649; 2012 IF: 2.355
Call Number UA @ lucian @ c:irua:100281 Serial 2773
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