Influence of interface transmissivity and inelastic scattering on the electronic entropy and specific heat of diffusive SNS Josephson junctions

TL;DR

This paper theoretically investigates how interface quality and inelastic scattering affect the electronic entropy and specific heat in diffusive SNS Josephson junctions, highlighting the impact of barriers and proposing an experimental measurement approach.

Contribution

It provides a detailed analysis of how non-idealities like barriers and scattering influence thermodynamic properties in SNS junctions, with practical experimental implications.

Findings

Barriers suppress superconducting correlations and reduce entropy and specific heat.

Spin-flip and inelastic scattering have minimal effects under typical conditions.

Proposes an experiment to measure phase-dependent specific heat in realistic setups.

Abstract

We study theoretically the electronic entropy and specific heat in diffusive superconductor-normal metal-superconductor (SNS) Josephson junctions. In particular, we consider the influence of non-idealities occurring in an actual experiment, such as the presence of barriers at the NS interfaces, the spin-flip and inelastic scattering in the N region and quasiparticle subgap states in the superconductors. We find that spin-flip and inelastic scattering do not have, for typical parameters values, a large effect. On the contrary, the presence of barriers suppresses the superconducting correlations in the N region, with the consequence that the entropy and the specific heat get reduced eventually to those in the absence of superconductivity for opaque interfaces. Finally we suggest an experiment and check that it is possible, under realistic conditions, to measure the dependence of electronic specific heat on the phase difference between the superconductors.