Charge quenching at defect states in transition metal dichalcogenide-graphene van der Waals heterobilayers

TL;DR

This paper investigates how defect states in transition metal dichalcogenide-graphene heterobilayers influence charge quenching, using a multidisciplinary approach to model electronic transitions and the effects of lattice symmetry and spin-orbit coupling.

Contribution

It introduces a minimal interacting model for defect charge dynamics in TMD-graphene heterobilayers, combining ab initio, model Hamiltonian, and density matrix methods.

Findings

Charge transition times are calculated for vacancy states.

Virtual charge fluctuations impact impurity state dynamics.

Spin-orbit interaction influences charge quenching mechanisms.

Abstract

We study the dynamical properties of point-like defects, represented by monoatomic chalcogen vacancies, in WS$_2$-graphene and MoS$_2$-graphene heterobilayers. Employing a multidisciplinary approach based on the combination of ab initio, model Hamiltonian and density matrix techniques, we propose a minimal interacting model that allows for the calculation of electronic transition times associated to population and depopulation of the vacancy by an additional electron. We obtain the "coarse-grained" semiclassical dynamics by means of a master equation approach and discuss the potential role of virtual charge fluctuations in the internal dynamics of impurity quasi-degenerate states. The interplay between the symmetry of the lattice and the spin degree of freedom through the spin-orbit interaction and its impact on charge quenching is studied in detail.