TY - JOUR
T1 - BCS superconductivity in metallic nanograins
T2 - Finite-size corrections, low-energy excitations, and robustness of shell effects
AU - García-García, Antonio M.
AU - Urbina, Juan Diego
AU - Yuzbashyan, Emil A.
AU - Richter, Klaus
AU - Altshuler, Boris L.
PY - 2011/1/20
Y1 - 2011/1/20
N2 - We combine the BCS self-consistency condition, a semiclassical expansion for the spectral density and interaction matrix elements to describe analytically how the superconducting gap depends on the size and shape of a two- and three-dimensional superconducting grain. In chaotic grains mesoscopic fluctuations of the matrix elements lead to a smooth dependence of the order parameter on the excitation energy. In the integrable case we find shell effects; i.e., for certain values of the electron number N a small change in N leads to large changes in the energy gap. With regard to possible experimental tests we provide a detailed analysis of the dependence of the gap on the coherence length and the robustness of shell effects under small geometrical deformations.
AB - We combine the BCS self-consistency condition, a semiclassical expansion for the spectral density and interaction matrix elements to describe analytically how the superconducting gap depends on the size and shape of a two- and three-dimensional superconducting grain. In chaotic grains mesoscopic fluctuations of the matrix elements lead to a smooth dependence of the order parameter on the excitation energy. In the integrable case we find shell effects; i.e., for certain values of the electron number N a small change in N leads to large changes in the energy gap. With regard to possible experimental tests we provide a detailed analysis of the dependence of the gap on the coherence length and the robustness of shell effects under small geometrical deformations.
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U2 - 10.1103/PhysRevB.83.014510
DO - 10.1103/PhysRevB.83.014510
M3 - Article
AN - SCOPUS:79551574194
SN - 1098-0121
VL - 83
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 1
M1 - 014510
ER -