Heat switch and thermoelectric effects based on Cooper-pair splitting and elastic cotunneling

TL;DR

This paper explores how a hybrid NSN structure can control heat flow and cooling at micro scales through Cooper pair splitting and elastic cotunneling, revealing novel thermoelectric effects.

Contribution

It provides a theoretical analysis of heat and electrical effects in NSN structures due to CPS and elastic cotunneling, highlighting potential for thermal device applications.

Findings

Superconductor mediates heat flow between normal leads.

CPS can occur in simple ballistic NSN structures.

Special cases challenge the second law of thermodynamics.

Abstract

In this paper, we demonstrate that the hybrid normal-superconducting-normal (NSN) structure has potential for a multifunctional thermal device which could serve for heat flux control and cooling of microstructures. By adopting the scattering matrix approach, we theoretically investigate thermal and electrical effects emerging in such structures due to the Cooper pair splitting (CPS) and elastic cotunneling phenomena. We show that a finite superconductor can, in principle, mediate heat flow between normal leads, and we further clarify special cases when this seems contradictory to the second law of thermodynamics. Among other things, we demonstrate that the CPS phenomenon can appear even in the simple case of a ballistic NSN structure.