Spin thermoelectrics in a disordered Fermi gas

TL;DR

This paper investigates the relationship between spin-heat and spin-charge responses in disordered Fermi gases with spin-orbit coupling, revealing potential for efficient heat-to-spin conversion in metallic systems.

Contribution

It derives a general expression linking spin-heat and spin-charge responses and explores various 2D systems to demonstrate the potential for heat-to-spin conversion efficiency.

Findings

The ratio of spin-heat to spin-charge response depends on spin-orbit coupling strength and type.

Metallic systems can be more efficient as heat-to-spin converters than as heat-to-charge.

Theoretical framework applies to different 2D electron and hole systems.

Abstract

We study the connection between the spin-heat and spin-charge response in a disordered Fermi gas with spin-orbit coupling. It is shown that the ratio between the above responses can be expressed as the thermopower $S=-(\pi k_B)^2T\sigma'/3e\sigma$ times a number $R_s$ which depends on the strength and type of the spin-orbit couplings considered. The general results are illustrated by examining different two-dimensional electron or hole systems with different and competing spin-orbit mechanisms, and we conclude that a metallic system could prove much more efficient as a heat-to-spin than as a heat-to-charge converter.