Gate tunability of highly efficient spin-to-charge conversion by spin Hall effect in graphene proximitized with WSe$_2$

TL;DR

This study demonstrates gate-controlled, highly efficient spin-to-charge conversion via the spin Hall effect in graphene/WSe2 heterostructures at room temperature, highlighting potential for spintronic device applications.

Contribution

First quantification of spin Hall effect in graphene/WSe2 at room temperature with gate tunability and record SCC length, showing no Rashba-Edelstein contribution.

Findings

Spin Hall effect dominates SCC in graphene/WSe2.

Gate voltage effectively controls SCC.

Achieved SCC length exceeds 20 nm.

Abstract

The proximity effect opens ways to transfer properties from one material into another and is especially important in two-dimensional materials. In van der Waals heterostructures, transition metal dichalcogenides (TMD) can be used to enhance the spin-orbit coupling of graphene leading to the prediction of gate controllable spin-to-charge conversion (SCC). Here, we report for the first time and quantify the SHE in graphene proximitized with WSe$_2$ up to room temperature. Unlike in other graphene/TMD devices, the sole SCC mechanism is the spin Hall effect and no Rashba-Edelstein effect is observed. Importantly, we are able to control the SCC by applying a gate voltage. The SCC shows a high efficiency, measured with an unprecedented SCC length larger than 20 nm. These results show the capability of two-dimensional materials to advance towards the implementation of novel spin-based devices and future applications.