Huge thermoelectric effects in ferromagnet-superconductor junctions in the presence of a spin-splitting field

TL;DR

This paper demonstrates that ferromagnet-superconductor junctions with spin-splitting fields exhibit exceptionally large thermoelectric effects, enabling high-efficiency heat-to-electricity conversion and spin-polarized current generation.

Contribution

It introduces a novel mechanism for large thermoelectric effects in superconductor-ferromagnet systems with spin-splitting fields, surpassing previous efficiencies.

Findings

Thermopower exceeds $k_B/e$ by a large factor

Thermoelectric figure of merit $ZT$ can far exceed unity

Spin-polarized currents can be generated by temperature bias

Abstract

We show that a huge thermoelectric effect can be observed by contacting a superconductor whose density of states is spin-split by a Zeeman field with a ferromagnet with a non-zero polarization. The resulting thermopower exceeds $k_B/e$ by a large factor, and the thermoelectric figure of merit $ZT$ can far exceed unity, leading to heat engine efficiencies close to the Carnot limit. We also show that spin-polarized currents can be generated in the superconductor by applying a temperature bias.