Re-entrant localization of single particle transport in disordered Andreev wires

TL;DR

This paper investigates how disorder affects low-energy single particle transport in normal-superconductor wires, revealing a re-entrant localization phenomenon due to competing effects of Andreev diffusion and particle-hole asymmetry.

Contribution

It introduces the concept of re-entrant localization in disordered Andreev wires, showing a non-monotonic dependence of conductance on mean free path due to combined diffusive effects.

Findings

Heat conductance decreases with increasing mean free path due to Andreev diffusion.

A small particle-hole asymmetry induces a diffusive drift that increases with mean free path.

Conductance exhibits a minimum as a function of mean free path, indicating re-entrant localization.

Abstract

We study effects of disorder on the low energy single particle transport in a normal wire surrounded by a superconductor. We show that the heat conductance includes the Andreev diffusion decreasing with increase in the mean free path $\ell $ and the diffusive drift produced by a small particle-hole asymmetry, which increases with increasing $\ell$. The conductance thus has a minimum as a function of $\ell$ which leads to a peculiar re-entrant localization as a function of the mean free path.