Extrinsic-Intrinsic Crossover of the Spin Hall Effect Induced by Alloying

TL;DR

This paper investigates how alloying Au-Cu influences the spin Hall effect, revealing a crossover from extrinsic to intrinsic mechanisms as Cu concentration varies, which advances understanding of spin-orbit physics.

Contribution

It demonstrates the alloying-induced crossover between extrinsic and intrinsic spin Hall effects in Au-Cu alloys, highlighting the tunability of spin Hall angle through composition.

Findings

Spin Hall angle changes sign with Cu concentration.

Intrinsic contribution dominates at higher Cu levels.

Extrinsic skew scattering causes sign reversal in a limited range.

Abstract

We report the observation of the crossover between the extrinsic and intrinsic spin Hall effect induced by alloying. We found that the spin Hall angle, the ratio of the spin Hall conductivity to the electric conductivity, changes drastically by tuning the composition of Au-Cu alloy. The spin Hall angle changes the sign only in a limited range of the Cu concentration due to the extrinsic skew scattering, while the intrinsic contribution becomes dominant with increasing the Cu concentration. This observation provides essential information for fundamental understanding of spin-orbit physics.