Induced valley splitting in monolayer MoS2 by an antiferromagnetic insulating CoO(111) substrate

The valleytronic properties in monolayer MoS2 induced by the magnetic proximity effect of an antiferromagnetic CoO(111) substrate have been investigated using density functional theory and Berry curvature calculations. The results show that monolayer MoS2 can achieve a large valley splitting of 103 meV when coupled to an antiferromagnetic insulating CoO(111) substrate, which is in a robust type-II antiferromagnetic state at room temperature. The substrate provides a Zeeman field of 152 T. Breaking of the time-reversal symmetry of monolayer MoS2 leads to a prominent anomalous Hall conductivity that has a quantized character in the range of the band edge at the K and K' valleys. Based on the result that the valley-contrasting Berry curvature is opposite at the K and K' valleys, a valleytronic device that can be used as a filter for both the valley and spin is proposed.