Efficient spin current source using a half-Heusler alloy topological semimetal with Back-End-of-Line compatibility

Abstract: Topological materials, such as topological insulators (TIs), have great potential for ultralow power spintronic devices, thanks to their giant spin Hall effect. However, the giant spin Hall angle (${\theta}{SH}$ > 1) is limited to a few chalcogenide TIs with toxic elements and low melting points, making them challenging for device integration during the silicon Back-End-of-Line (BEOL) process. Here, we show that by using a half-Heusler alloy topological semi-metal (HHA-TSM), YPtBi, it is possible to achieve both a giant ${\theta}{SH}$ up to 1.6 and a high thermal budget up to 600${\deg}$C. We demonstrate magnetization switching of a CoPt thin film using the giant spin Hall effect of YPtBi by current densities lower than those of heavy metals by one order of magnitude. Since HHA-TSM includes a group of three-element topological materials with great flexibility, our work opens the door to the third-generation spin Hall materials with both high ${\theta}_{SH}$ and high compatibility with the BEOL process that would be easily adopted by the industry.