Spin Hall effects due to phonon skew scattering

TL;DR

This paper investigates phonon skew scattering as a high-temperature mechanism for spin Hall effects in metals, revealing its temperature independence above the Debye temperature and its implications for spin Hall angle behavior.

Contribution

It introduces the concept of phonon skew scattering as a significant high-temperature contribution to spin Hall effects, extending understanding beyond Mott skew scattering.

Findings

Spin Hall conductivity due to phonon skew scattering is temperature-independent above T_D.

High-T linear behavior of spin Hall angle indicates extrinsic scattering dominance when intrinsic spin splitting is small.

Phonon skew scattering is relevant for experimental observations of spin Hall effects at high temperatures.

Abstract

A diversity of spin Hall effects in metallic systems is known to rely on Mott skew scattering. In this work its high-temperature counterpart, phonon skew scattering, which is expected to be of foremost experimental relevance, is investigated. In particular, the phonon skew scattering spin Hall conductivity is found to be practically $T$-independent for temperatures above the Debye temperature $T_D$. As a consequence, in Rashba-like systems a high-$T$ linear behavior of the spin Hall angle demonstrates the dominance of extrinsic spin-orbit scattering only if the intrinsic spin splitting is smaller than the temperature.