Graphene on transition-metal dichalcogenides: a platform for proximity spin-orbit physics and optospintronics

TL;DR

This paper demonstrates that graphene on transition-metal dichalcogenides exhibits enhanced proximity spin-orbit coupling and tunable electronic properties, offering new opportunities for spintronics and optospintronics applications.

Contribution

It provides first-principles calculations showing giant proximity spin-orbit effects and tunable Fermi levels in graphene/TMDC hybrids, proposing their use in advanced spintronic devices.

Findings

Giant proximity spin-orbit coupling in graphene on MoS2

Fermi level tuning via electric field crossing MoS2 conduction band

Potential for optical spin injection and spin transfer studies

Abstract

Hybrids of graphene and two dimensional transition metal dichalcogenides (TMDC) have the potential to bring graphene spintronics to the next level. As we show here by performing first-principles calculations of graphene on monolayer MoS$_2$, there are several advantages of such hybrids over pristine graphene. First, Dirac electrons in graphene exhibit a giant global proximity spin-orbit coupling, without compromising the semimetallic character of the whole system at zero field. Remarkably, these spin-orbit effects can be very accurately described by a simple effective Hamiltonian. Second, the Fermi level can be tuned by a transverse electric field to cross the MoS$_2$ conduction band, creating a system of coupled massive and massles electron gases. Both charge and spin transport in such systems should be unique. Finally, we propose to use graphene/TMDC structures as a platform for optospintronics, in particular for optical spin injection into graphene and for studying spin transfer between TMDC and graphene.