Optimal charge-to-spin conversion in graphene on transition metal dichalcogenide

Manuel Offidani, Mirco Milletarí, Roberto Raimondi, Aires Ferreira

Published 2017-06-27Version 1

When graphene is paired with a semiconducting transition metal dichalcogenide (TMD) monolayer its band structure develops rich spin textures due to proximity spin-orbital effects with interfacial breaking of inversion symmetry. In this work, we show that the characteristic spin winding of low-energy states in graphene on TMD enables current-driven spin polarization, a phenomenon known as the inverse spin galvanic effect (ISGE). By introducing a proper figure of merit, we quantify the efficiency of charge-to-spin conversion and show it is close to unit when the Fermi level approaches the spin minority band. Remarkably, at high electronic density, even though sub-bands with opposite spin helicities are occupied, the efficiency decays only algebraically. The giant ISGE predicted for graphene on TMD monolayers is robust against disorder and remains large at room temperature.