Anisotropic spin Hall effect from first principles

TL;DR

This paper presents first principles calculations revealing significant anisotropy in the intrinsic spin Hall conductivity of nonmagnetic hcp metals and antiferromagnetic Cr, with implications for tuning spin polarization directions.

Contribution

It introduces a theoretical framework linking the SHC vector to spin polarization direction and predicts tunable spin Hall effects based on anisotropy in hcp metals.

Findings

Large anisotropies in SHC for most studied metals

Derived relation between SHC vector and spin polarization

Predicted tunability of spin polarization direction

Abstract

We report on first principles calculations of the anisotropy of the intrinsic spin Hall conductivity (SHC) in nonmagnetic hcp metals and in antiferromagnetic Cr. For most of the metals of this study we find large anisotropies. We derive the general relation between the SHC vector and the direction of spin polarization and discuss its consequences for hcp metals. Especially, it is predicted that for systems where the SHC changes sign due to the anisotropy the spin Hall effect may be tuned such that the spin polarization is parallel either to the electric field or to the spin current.