Correlation-induced refrigeration with superconducting single-electron transistors

TL;DR

This paper introduces a superconducting tunnel junction model that refrigerates a nearby metallic island through charge fluctuations, highlighting the role of Coulomb interaction and superconducting gap in reducing power consumption and achieving significant cooling.

Contribution

It presents a novel mechanism for refrigeration via correlation-induced heat transfer without particle exchange, emphasizing non-equilibrium correlations in mesoscopic conductors.

Findings

Cooling from 200 mK to 50 mK predicted

Power consumption is reduced by Coulomb interaction and superconducting gap

Mechanism enables local temperature gradients in tunnel junction arrays

Abstract

A model of a superconducting tunnel junction which refrigerates a nearby metallic island without any particle exchange is presented. Heat extraction is mediated by charge fluctuations in the coupling capacitance of the two systems. The interplay of Coulomb interaction and the superconducting gap reduces the power consumption of the refrigerator. The island is predicted to be cooled from lattice temperatures of 200~mK down to close to 50~mK, for realistic parameters. The results emphasize the role of non-equilibrium correlations in bipartite mesoscopic conductors. This mechanism can be applied to create local temperature gradients in tunnel junction arrays or explore the role of interactions in the thermalization of non-equilibrium systems.