Microscopic theory of band gap opening and spin-orbit splitting in graphene/TMDC heterobilayers

Bilayers of graphene and monolayer transition metal dichalcogenides (TMDCs) are fascinating van der Waals heterostructures with an interesting electronic band structure. Theoretical ab initio calculations have shown a gap opening and an induced spin-orbit splitting in the band structure of graphene from the TMDC layer [1, 2]. These results have been experimentally confirmed by recent magnetotransport experiments showing weak antilocalisation (WAL) [2, 3]. Using perturbation theory, we propose a microscopic model to explain the origin of the gap and of the spin-orbit splitting. We also consider the dependence of the spin-orbit splitting on the misalignment of graphene and TMDC layers.

[1] M. Gmitra, D. Kochan, P. Högl, and J. Fabian, Phys. Rev. B 93, 155104 (2016).
[2] Z. Wang, D.-K. Ki, H. Chen, H. Berger, A. H. MacDonald, and A. F. Morpurgo, Nat. Comm. 6, 8339 (2015).
[3] T. Wakamura, F. Reale, P. Palczynski, S. Guéron, C. Mattevi, and H. Bouchiat, Phys. Rev. Lett. 120, 106802 (2018).