Spin-orbit proximity in van der Waals heterostructures (Conference Presentation)

Abstract

Transition metal dichalcogenides (TMD) can be used to enhance the spin-orbit coupling of graphene, leading to new spin transport channels with unprecedented spin textures. We have optimized bilayer graphene/WSe2 van der Waals heterostructures to achieve magnetic-field-free spin precession. Remarkably, the sign of the precessing spin polarization can be tuned electrically by backgate voltage and drift current, being the first realization of a spin field-effect transistor at room temperature in a diffusive system. The spin-orbit proximity in graphene/TMD van der Waals heterostructures also leads to spin Hall effect (SHE), first observed by our group using MoS2 as the TMD. The combination of long-distance spin transport and SHE in the same material gives rise to an unprecedented figure of merit (product of spin Hall angle and spin diffusion length) of 40 nm in graphene proximitized with WSe2, which is also gate tunable.