Heat transport in proximity structures

TL;DR

This paper investigates heat and charge transport in diffusive normal-superconductor structures, revealing suppressed thermal flow due to Andreev reflection and oscillations in thermal conductance with phase difference, aligning with recent experimental findings.

Contribution

It provides a detailed analysis of thermal transport behavior in diffusive proximity structures, highlighting the suppression of subgap thermal flow and phase-dependent oscillations.

Findings

Subgap thermal flow is suppressed and approaches zero at low temperatures.

Thermal conductance exhibits full-scale oscillations with phase difference.

Electric conductance shows a reentrance effect.

Abstract

We study heat and charge transport through a normal diffusive wire coupled with a superconducting wire over the region smaller than the coherence length. Due to partial Andreev reflection of quasiparticles from the interface, the subgap thermal flow is essentially suppressed and approaches zero along with energy, which is specific for diffusive structures. Whereas the electric conductance shows conventional reentrance effect, the thermal conductance rapidly decreases with temperature which qualitatively explains the results of recent experiments. In the Andreev interferometer geometry, the thermal conductance experiences full-scale oscillations with the order parameter phase difference.