BCS superconductivity in metallic nanograins: Finite-size corrections, low energy excitations, and robustness of shell effects - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




BCS superconductivity in metallic nanograins: Finite-size corrections, low energy excitations, and robustness of shell effects - Condensed Matter > Mesoscale and Nanoscale Physics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We combine the BCS self-consistency condition, a semiclassical expansion forthe spectral density and interaction matrix elements to describe analyticallyhow the superconducting gap depends on the size and shape of a 2d and 3dsuperconducting grain. In chaotic grains mesoscopic fluctuations of the matrixelements lead to a smooth dependence of the order parameter on the excitationenergy. In the integrable case we find shell effects i. e. for certain valuesof the electron number $N$ a small change in N leads to large changes in theenergy gap. With regard to possible experimental tests we provide a detailedanalysis of the dependence of the gap on the coherence length and therobustness of shell effects under small geometrical deformations.



Author: Antonio M. Garcia-Garcia, Juan Diego Urbina, Emil A. Yuzbashyan, Klaus Richter, Boris L. Altshuler

Source: https://arxiv.org/



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