Superconductivity in disordered thin films: giant mesoscopic fluctuations

TL;DR

This paper investigates how mesoscopic fluctuations in disordered thin superconducting films become significantly enhanced near the critical conductance, causing spatial inhomogeneities and a percolative transition.

Contribution

It reveals the crucial role of mesoscopic fluctuations near the critical conductance, highlighting their impact on the inhomogeneous superconducting transition.

Findings

Mesoscopic fluctuations are amplified near the critical conductance g_c.

Superconductivity becomes spatially inhomogeneous due to these fluctuations.

The transition exhibits a percolative nature caused by local variations in T_c.

Abstract

We discuss intrinsic inhomogeneities of superconductive properties of uniformly disordered thin films with large dimensionless conductance g. It is shown that mesoscopic fluctuations, which usually contain a small factor 1/g, are crucially enhanced near the critical conductance g_c >> 1 where superconductivity is destroyed at T=0 due to Coulomb suppression of the Cooper attraction. This leads to strong spatial fluctuations of the local transition temperature and thus to percolative nature of the thermal superconductive transition.