Enhancement of superconductivity by Anderson localization

TL;DR

This paper investigates how Anderson localization, through disorder effects, can significantly enhance the superconducting transition temperature (T_c) in various two-dimensional regimes, highlighting the role of wave function multifractality.

Contribution

It introduces a sigma-model renormalization group analysis that incorporates electron-electron interactions to demonstrate T_c enhancement due to Anderson localization.

Findings

Anderson localization leads to strong T_c enhancement.

Multifractal wave functions are key to T_c increase.

Results apply to weak localization, antilocalization, and near mobility edge regimes.

Abstract

Influence of disorder on the temperature of superconducting transition (T_c) is studied within the sigma-model renormalization group framework. Electron-electron interaction in particle-hole and Cooper channels is taken into account and assumed to be short-range. Two-dimensional systems in the weak localization and antilocalization regime, as well as systems near mobility edge are considered. It is shown that in all these regimes the Anderson localization leads to strong enhancement of T_c related to the multifractal character of wave functions.