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Role of Spatial Amplitude Fluctuations in Highly Disordered s-Wave Superconductors

Amit Ghosal·Mohit Randeria·Nandini Trivedi
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Abstract

The effect of non-magnetic impurities on 2D s-wave superconductors is studied beyond the weak disorder regime. Within the Bogoliubov-de Gennes (BdG) framework, the local pairing amplitude develops a broad distribution with significant weight near zero with increasing disorder. Surprisingly, the density of states continues to show a finite spectral gap. The persistence of the spectral gap at large disorder is shown to arise from the break up of the system into superconducting "islands". Superfluid density and off-diagonal correlations show a substantial reduction at high disorder.A simple analysis of phase fluctuations in the highly inhomogeneous BdG state is shown to lead to a transition to a non-superconducting state.

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Amit Ghosal, Mohit Randeria, Nandini Trivedi. 1998-10-17. Role of Spatial Amplitude Fluctuations in Highly Disordered s-Wave Superconductors. https://doi.org/10.1103/physrevlett.81.3940

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