Coulomb Center in a Transition Metal Dichalcogenide Monolayer

Electronic processes involving a charged impurity in a transition metal dichalcogenide monolayer and in gapped graphene have been theoretically studied. The spectrum of bound states, the transport cross section for scattering of electrons on a charged donor center, and the donor photoionization probability have been calculated within the minimal two-band model. The last parameter has a significant valley selectivity.