Giant Intrinsic Spin Hall Effect in W$_3$Ta and other A15 Superconductors

TL;DR

This paper predicts large intrinsic spin Hall effects in certain superconductors like W3Ta and others, based on their electronic structure and topological properties, which could advance spintronic applications.

Contribution

It introduces a strategy to identify materials with large intrinsic SHEs by analyzing their electronic band topology and symmetry properties.

Findings

W3Ta, Ta3Sb, and Cr3Ir exhibit high spin Hall conductivities.

Large SHEs are linked to gapped Dirac crossings caused by SOC.

A simple search strategy for materials with large SHEs is proposed.

Abstract

The spin Hall effect (SHE) is the conversion of charge current to spin current, and non-magnetic metals with large SHEs are extremely sought after for spintronic applications, but their rarity has stifled widespread use. Here we predict and explain the large intrinsic SHE in $\beta$-W and the A15 family of superconductors: W$_3$Ta, Ta$_3$Sb, and Cr$_3$Ir having spin hall conductivities (SHC) of -2250, -1400, and 1210 $\frac{\hbar}{e}(\Omega cm)^{-1}$, respectively. Combining concepts from topological physics with the dependence of the SHE on the spin Berry curvature (SBC) of the electronic bands, we propose a simple strategy to rapidly search for materials with large intrinsic SHEs based on the following ideas: high symmetry combined with heavy atoms gives rise to multiple Dirac-like crossings in the electronic structure, without sufficient symmetry protection these crossings gap due to spin orbit coupling (SOC), and gapped Dirac crossings create large spin Berry curvature.