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

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 ${\hat{I}}^2$-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 $\frac{\hslash }{e}(\hat{I}\text{c◯}cm{)}^{-1}$, 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.