Spin-orbit phenomena in proximitized graphene

When graphene is in proximity to a transition metal dichalcogenide (TMDC), it acquires an enhanced spin-orbit interaction (SOI) together with a complex spin texture with out-of-plane and winding in-plane components. In this talk, I will discuss the relevant consequences of this unique type of SOI for spin manipulation in graphene-TMDC heterostructures.  Firstly, I will present our recent experiments which demonstrate how the spin dynamics in graphene is strongly modified by the proximity to a TMDC. The results show that the spin lifetime depends on the spin orientation, and it is larger for spins pointing out of the graphene plane compared with the spins pointing in-plane. Such anisotropic features indicate that the spin–valley coupling present in the TMDC is imprinted in the graphene and felt by the propagating spins [1,2]. I will further present an unprecedented electric-field tunability of the spin relaxation in graphene-WS2 heterostructures. The characteristic spin relaxation varies from highly anisotropic to nearly isotropic when the applied an electric field. Finally, I will demonstrate that the enhanced SOI leads to spin-charge interconversion in graphene. By using spin precession measurements, we can separate the contributions of the spin Hall effect (SHE) and the spin galvanic effect (SGE). Remarkably, their corresponding conversion efficiencies can be tailored by electrostatic gating in magnitude and sign [3].