Valley-resolved quantum anomalous Hall effect in ferromagnetically proximitized monolayer MoTe2

Abstract

We theoretically investigate the effect of Rashba field and magnetic exchange interaction on the topological properties of monolayer transition-metal dichalcogenides (TMDs) based on a tight-binding model. The tight-binding Hamiltonian incorporates magnetic exchange interaction and the Rashba field which can be induced by proximity to a ferromagnetic (FM) substrate, such as europium oxide (EuO) or similar materials. Through tuning the Rashba field and magnetic exchange interaction, we find a quantum state of matter---the valley-resolved quantum anomalous Hall state---in monolayer ${\mathrm{MoTe}}_{2}$. The most amazing property of this topological quantum state is that the edge states of this phase are all located only at valley $\ensuremath{-}K$ (or $+K$), i.e., they are completely valley resolved. Additionally, the calculated Chern number $\mathcal{C}=\ensuremath{-}2$ indicates that there are two pairs of valley-resolved chiral edge modes at the boundaries of the monolayer ${\mathrm{MoTe}}_{2}$ nanoribbon. The electronic transmission demonstrates the robustness of the edge states of the valley-resolved quantum anomalous Hall effect against defects. This newfound valley-resolved quantum anomalous Hall effect provides an idea for designing dissipationless valleytronics utilizing TMD/FM heterojunctions.