Effect of valley, spin, and band nesting on the electronic properties of gated quantum dots in a single layer of transition metal dichalcogenides

摘要

We present here results of an atomistic theory of electrons confined by metallic gates in a single layer of transition metal dichalcogenides. The electronic states are described by the tight-binding model and computed using a computational box with periodic boundary conditions including up to millions of atoms. The confinement is modelled with a parabolic confining potential over the computational box. With this methodology applied to MoS_2, we find a twofold degenerate energy spectrum of electrons confined in the two nonequivalent K valleys by the metallic gates as well as sixfold degenerate spectrum associated with Q valleys. We compare the electron spectrum with the energy levels of electrons confined in GaAs/GaAIAs and in self-assembled quantum dots. We discuss the role of spin splitting and topological moments on the K and Q valley electronic states in quantum dots with sizes comparable to experiment.