Kinetic equation approach to diffusive superconducting hybrid devices

TL;DR

This paper investigates the temperature-dependent electrostatic and chemical potential distributions in disordered normal metal-superconductor structures, proposing experiments and analyzing resistance changes due to various mechanisms, including Andreev reflection.

Contribution

It introduces a detailed kinetic equation approach to analyze potential distributions and resistance changes in diffusive superconducting hybrid devices, highlighting a novel zero-temperature effect.

Findings

Potential distributions differ significantly with a superconducting terminal.

The resistance change due to the new effect is comparable to the interaction parameter.

Thermal effects on resistance due to Andreev reflection are generally larger.

Abstract

We present calculations of the temperature-dependent electrostatic and chemical potential distributions in disordered normal metal-superconductor structures. We show that they differ appreciably in the presence of a superconducting terminal and propose an experiment to measure these two different potential distributions. We also compute the resistance change in these structures due to a recently proposed mechanism which causes a finite effect at zero temperature. The relative resistance change due to this effect is of the order of the interaction parameter in the normal metal. Finally a detailed calculation of the resistance change due to the temperature dependence of Andreev reflection in diffusive systems is presented. We find that the maximal magnitude due to this thermal effect is in general much larger than the magnitude of the novel effect.