Non-equilibrium and proximity effects in superconductor-normal metal junctions

TL;DR

This paper investigates non-equilibrium heating and inverse proximity effects in NISIN junctions, providing numerical and analytical insights relevant for designing efficient SINIS coolers with quasiparticle traps.

Contribution

It offers a detailed analysis of non-equilibrium and proximity effects in superconductor-normal metal junctions using both numerical solutions and analytical approximations.

Findings

Numerical solutions of Usadel equations reveal the impact of non-equilibrium heating.

Analytical approximations are derived for short and long junction limits.

Results inform the design of SINIS coolers with improved quasiparticle management.

Abstract

We study the consequences of non-equilibrium heating and inverse proximity effect in normal metal - insulator - superconductor - insulator - normal metal (NISIN) junctions with a simple quasi-one-dimensional model. We especially focus on observables and parameter regions that are of interest in the design of SINIS coolers with quasiparticle traps. We present numerical results calculated by solving the Usadel equation and also present analytical approximations in two limiting cases: a short junction with a non-negligible resistance in both ends and a long junction with a transparent contact at one end.