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“Superconducting nanowires: quantum-confinement effect on the critical magnetic field and supercurrent”. Croitoru MD, Shanenko AA, Peeters FM, , 327 (2010). http://doi.org/10.1142/9789814289153_0025
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.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
DOI: 10.1142/9789814289153_0025
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“Hollow nanocylinder: multisubband superconductivity induced by quantum confinement”. Chen Y, Shanenko AA, Peeters FM, Physical review : B : condensed matter and materials physics 81, 134523 (2010). http://doi.org/10.1103/PhysRevB.81.134523
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 21
DOI: 10.1103/PhysRevB.81.134523
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“Superconducting nanowires: quantum-confinement effect on the critical magnetic field and supercurrent”. Croitoru MD, Shanenko AA, Peeters FM, 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 23, 4257 (2009). http://doi.org/10.1142/S0217979209063419
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 0.736
Times cited: 1
DOI: 10.1142/S0217979209063419
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“Tuning the superconducting properties of nanomaterials”. Croitoru MD, Shanenko AA, Peeters FM Springer, Dordrecht, page 1 (2009).
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.
Keywords: H1 Book chapter; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
DOI: 10.1007/978-90-481-3120-4_1
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“Superconducting nanowires: quantum confinement and spatially dependent Hartree-Fock potential”. Chen Y, Croitoru MD, Shanenko AA, Peeters FM, Journal of physics : condensed matter 21, 435701 (2009). http://doi.org/10.1088/0953-8984/21/43/435701
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 12
DOI: 10.1088/0953-8984/21/43/435701
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“Superconducting nanowires: interplay of discrete transverse modes with supercurrent”. Croitoru MD, Shanenko AA, Kaun CC, Peeters FM, Physical review : B : solid state 80, 024513 (2009). http://doi.org/10.1103/PhysRevB.80.024513
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 21
DOI: 10.1103/PhysRevB.80.024513
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“Andreev-type states induced by quantum confinement”. Shanenko AA, Croitoru MD, Mints RG, Peeters FM, Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques 2, 611 (2008). http://doi.org/10.1134/S1027451008040216
Abstract: The properties of a clean superconductor with nanoscale dimensions are governed by quantum confinement of the electrons. This results in a spatially inhomogeneous superconducting condensate and in the formation of new Andreev-type quasiparticle states. These states are mainly located beyond regions where the superconducting condensate is enhanced. A numerical self-consistent solution of the Bogoliubov-de Gennes equations for a cylindrical metallic nanowire shows that these new Andreev-type states decrease the ratio of the energy gap to the critical temperature.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1134/S1027451008040216
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“Superconducting nanofilms: Andreev-type states induced by quantum confinement”. Shanenko AA, Croitoru MD, Peeters FM, Physical review : B : solid state 78, 054505 (2008). http://doi.org/10.1103/PhysRevB.78.054505
Abstract: Quantum confinement of the transverse electron motion is the major effect governing the superconducting properties of high-quality metallic nanofilms, leading to a nonuniform transverse distribution of the superconducting condensate. In this case the order parameter can exhibit significant local enhancements due to these quantum-size effects and, consequently, quasiparticles have lower energies when they avoid the local enhancements of the pair condensate. Such excitations can be considered as new Andreev-type quasiparticles but now induced by quantum confinement. By numerically solving the Bogoliubovde Gennes equations and using Anderson's approximate solution to these equations, we: (a) formulate a criterion for such new Andreev-type states (NATS) and (b) study their effect on the superconducting characteristics in metallic nanofilms. We also argue that nanofilms made of low-carrier-density materials, e.g., of superconducting semiconductors, can be a more optimal choice for the observations of NATS and other quantum-size superconducting effects.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 14
DOI: 10.1103/PhysRevB.78.054505
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“Magnetic-field induced quantum-size cascades in superconducting nanowires”. Shanenko AA, Croitoru MD, Peeters FM, Physical review : B : condensed matter and materials physics 78, 024505 (2008). http://doi.org/10.1103/PhysRevB.78.024505
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 42
DOI: 10.1103/PhysRevB.78.024505
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“Nanoscale superconductivity: nanowires and nanofilms”. Shanenko AA, Croitoru MD, Peeters FM, Physica: C : superconductivity 468, 593 (2008). http://doi.org/10.1016/j.physc.2007.11.053
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 6
DOI: 10.1016/j.physc.2007.11.053
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“Nanowires and nanofilms: superconductivity in quantum-size regime”. Peeters FM, Croitoru MD, Shanenko AA, Physica: C : superconductivity 468, 326 (2008). http://doi.org/10.1016/j.physc.2007.07.013
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 3
DOI: 10.1016/j.physc.2007.07.013
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“Generalized Galitskii approach for the vertex function of a Fermi gas with resonant interaction”. Vagov A, Schomerus H, Shanenko A, Physical review : B : condensed matter and materials physics 76, 214513 (2007). http://doi.org/10.1103/PhysRevB.76.214513
Abstract: We present a generalized Galitskii approach for the Bethe-Salpeter equation for the two-particle vertex function of a Fermi system with the resonant interaction by accounting for the resonant state in the scattering potential and utilizing the universal form of the resonant scattering amplitude. The procedure can be carried out both for the normal as well as for the condensate state. In both cases, the vertex function in the vicinity of the resonance is shown to formally coincide with that obtained for a weakly attractive Fermi gas. Thus we justify the popular calculational framework in which results for the weakly attractive Fermi gas are formally extrapolated into the domain of strong coupling, and further to the repulsive side of the resonance, where molecular states are formed.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 8
DOI: 10.1103/PhysRevB.76.214513
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“New Andreev-type states in superconducting nanowires”. Shanenko AA, Croitoru MD, Mints RG, Peeters FM, Physical review letters 99, 067007 (2007). http://doi.org/10.1103/PhysRevLett.99.067007
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 8.462
Times cited: 30
DOI: 10.1103/PhysRevLett.99.067007
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“Dependence of superconducting properties on the size and shape of a nanoscale superconductor: from nanowire to film”. Croitoru MD, Shanenko AA, Peeters FM, Physical review : B : condensed matter and materials physics 76, 024511 (2007). http://doi.org/10.1103/PhysRevB.76.024511
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 54
DOI: 10.1103/PhysRevB.76.024511
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“Oscillations of the superconducting temperature induced by quantum well states in thin metallic films: numerical solution of the Bogoliubov-de Gennes equations”. Shanenko AA, Croitoru MD, Peeters FM, Physical review : B : condensed matter and materials physics 75, 014519 (2007). http://doi.org/10.1103/PhysRevB.75.014519
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 85
DOI: 10.1103/PhysRevB.75.014519
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“Quantum-size effects on T-c in superconducting nanofilms”. Shanenko AA, Croitoru MD, Peeters FM, Europhysics letters 76, 498 (2006). http://doi.org/10.1209/epl/i2006-10274-6
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 1.957
Times cited: 31
DOI: 10.1209/epl/i2006-10274-6
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“Size-dependent enhancement of superconductivity in Al and Sn nanowires: shape-resonance effect”. Shanenko AA, Croitoru MD, Zgirski M, Peeters FM, Arutyunov K, Physical review : B : condensed matter and materials physics 74, 052502 (2006). http://doi.org/10.1103/PhysRevB.74.052502
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 95
DOI: 10.1103/PhysRevB.74.052502
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“Shape resonances in the superconducting order parameter of ultrathin nanowires”. Shanenko AA, Croitoru MD, Physical review : B : condensed matter and materials physics 73, 012510 (2006). http://doi.org/10.1103/PhysRevB.73.012510
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 41
DOI: 10.1103/PhysRevB.73.012510
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“Imperfect fermi gas : kinetic and interaction energies”. Shanenko AA, Physical review : A : atomic, molecular and optical physics 70, 063618 (2004). http://doi.org/10.1103/PhysRevA.70.063618
Abstract: A uniform ground-state three-dimensional Fermi gas with short-range repulsive pairwise interaction is under consideration. Its kinetic and interaction energies are calculated up to the second order of the expansion in the gas parameter. Similar to recent results for an interacting Bose gas, the quantities in question are found to depend on the pairwise interaction through two characteristic lengths: the former, a, is the s-wave scattering length, and the latter, b, is related to a by b=a-m(partial derivativea/partial derivativem), where m stands for the fermion mass. To control the results, we proceed in two independent ways. The first involves the Hellmann-Feynman theorem applied to derive the kinetic and interaction energies from the total-energy expansion in the gas parameter first found by Huang and Yang. The second way operates with in-medium pair wave functions and allows one to calculate the quantities of interest “from scratch.” The results of the present investigation, taken together with those of the recent consideration of a dilute Bose gas, make it possible to conclude that the pairwise interaction in a quantum gas has an essential and nontrivial effect on the kinetic energy, which is not the case for a classical many-particle system.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.925
DOI: 10.1103/PhysRevA.70.063618
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“Mesoscopic samples: the superconducting condensate via the Gross.Pitaevskii scenario”. Shanenko AA, Tempère J, Brosens F, Devreese JT, Solid state communications 131, 409 (2004). http://doi.org/10.1016/j.ssc.2004.03.019
Keywords: A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
Impact Factor: 1.554
Times cited: 1
DOI: 10.1016/j.ssc.2004.03.019
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“Effects of confining interaction in meso-superconductors”. Shanenko AA, Ivanov VA, Physics letters : A 322, 384 (2004). http://doi.org/10.1016/j.physleta.2004.01.042
Abstract: This Letter presents a generalized Ginzburg-Landau equation for the superconducting order parameter which includes the terms resulting from the confining interaction associated with the specimen boundary. While the original Ginzburg-Landau theory had been developed for a bulk superconductor, this generalization is meant for study of a meso-superconductor. (C) 2004 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.772
Times cited: 1
DOI: 10.1016/j.physleta.2004.01.042
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“Stability criterion for large bipolarons in a polaron-gas background”. Smondyrev MA, Shanenko AA, Devreese JT, Physical review : B : condensed matter and materials physics 63, 024302 (2001)
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 3.836
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“Superconductivity in the quantum-size regime”. Shanenko AA, Croitoru MD, Peeters FM, , 79 (2008)
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.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
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