Spin-orbit proximity in van der Waals heterostructures

Abstract

In this thesis, graphene/transition metal dichalcogenides van der Waals hetero-structures were used to develop a device that combines Hall probes with ferromagnetic electrodes. With it, the spin Hall effect in graphene induced by spin-orbit coupling proximity with MoS2 and WSe2 could unambiguously be demonstrated. The Hanle precession of the non-local resistance not only gives convincing experimental proof but also allows the quantification of the spin transport and the spin-to-charge conversion. The fact that both occur in different parts of the same material gives rise to a high efficiency for the voltage output up to room temperature. Additionally, the control by applying a gate voltage was shown in graphene proximitized with WSe2, enabling a record efficiency measured of around 40 nm. Additionally, in a graphene/WSe2 lateral spin valve, coherent, electrically controllable spin precession in the absence of an external magnetic field was achieved, even in the diffusive regime.