We report a systematic study on strong enhancement of spin-orbit interaction (SOI) in graphene driven by transition-metal dichalcogenides (TMDs). Low temperature magnetotoransport measurements of graphene proximitized to different TMDs (monolayer and bulk WSe2, WS2 and monolayer MoS2) all exhibit weak antilocalization peaks, a signature of strong SOI induced in graphene. The amplitudes of the induced SOI are different for different materials and thickness, and we find that monolayer WSe2 and WS2 can induce much stronger SOI than bulk ones and also monolayer MoS2. The estimated spin-orbit (SO) scattering strength for the former reaches ∼ 10 meV whereas for the latter it is around 1 meV or less. We also discuss the symmetry and type of the induced SOI in detail, especially focusing on the identification of intrinsic and valley-Zeeman (VZ) SOI via the dominant spin relaxation mechanism. Our findings offer insight on the possible realization of the quantum spin Hall (QSH) state in graphene.
@article{arxiv.1809.06230,
title = {Spin-Orbit Interaction Induced in Graphene by Transition-Metal Dichalcogenides},
author = {T. Wakamura and F. Reale and P. Palczynski and M. Q. Zhao and A. T. C. Johnson and S. Guéron and C. Mattevi and A. Ouerghi and H. Bouchiat},
journal= {arXiv preprint arXiv:1809.06230},
year = {2019}
}