Giant intrinsic spin Hall effect in the TaAs family of Weyl semimetals

TL;DR

This paper predicts that Weyl semimetals, specifically the TaAs family, exhibit a large intrinsic spin Hall effect due to their bulk band structure, offering promising applications in spintronics.

Contribution

It demonstrates, through ab initio calculations, that Weyl semimetals have a large intrinsic spin Hall effect comparable to transition metals, providing a new avenue for spintronic materials.

Findings

Large spin Hall conductivity in Weyl semimetals.

Intrinsic origin of spin Hall effect from bulk band structure.

Potential for spintronics applications without bulk doping issues.

Abstract

Since their discovery, topological insulators have been expected to be ideal spintronic materials owing to the spin currents carried by surface states with spin--momentum locking. However, the bulk doping problem remains an obstacle that hinders such application. In this work, we predict that a newly discovered family of topological materials, the Weyl semimetals, exhibits large intrinsic spin Hall effects that can be utilized to generate and detect spin currents. Our $ab~initio$ calculations reveal a large spin Hall conductivity that is comparable to that of $4d$ and $5d$ transition metals. The spin Hall effect originates intrinsically from the bulk band structure of Weyl semimetals, which exhibit a large Berry curvature and spin--orbit coupling, so the bulk carrier problem in the topological insulators is naturally avoided. Our work not only paves the way for employing Weyl semimetals in spintronics, but also proposes a new guideline for searching for the spin Hall effect in various topological materials.