Dirac-Rashba fermions and quantum valley Hall insulators in graphene-based 2D heterostructures

This is the authors' abstract. We don't add key points for this paper.

For promising Dirac electronic properties and functionalities, we study five 2D heterostructures consisting of graphene and monolayer transition metal dichalcogenides by means of first-principles investigation and an effective low-energy model. It is revealed from first-principles bands that the Dirac energy bands are gapped (0.1 ∼ 0.5 meV) and their relativistic dispersions are robust up to the energy window of 0.4 eV at least. The model parameters are determined by fitting the first-principles calculated bands in each of the heterostructures. It is shown that Dirac-Rashba fermions are hosted in the WSe2/graphene and MoSe2/graphene/WSe2, and quantum valley Hall insulators can be achieved in all these heterostructures. Further analysis elucidates features of Berry curvature distribution and interactions of the orbitals and spins. These can be useful in future exploration for more effects and functionalities in 2D heterostructures.