First Principle Calculations of Magnetic Proximity Effect Induced Valley Splitting on Heterointerface WS₂/CoO(111)

Abstract

The first principle density functional theory calculation has been done for calculating electronic and valleytronic properties on WS2/CoO(111) heterointerface. We have performed the structural optimization of the WS2/CoO(111) heterointerface and obtained the most stable structures by evaluating the binding energy between WS2 and CoO(111) surface. Electronic and valleytronic properties can be understood by band structures, density of states, and spin texture of the crystal models. The results show that non-magnetic WS2 becomes ferromagnetic because of the interfacial effect with the CoO(111) surface. The presence of CoO(111) near the WS2 gives magnetic induction which breaks the time-reversal symmetry preserved on non-magnetic WS2. Accordingly, the largest valley degeneracy is observed at Q and Q’ point in the unoccupied state, with the valley splitting up to 186 meV. Furthermore, the out-of-plane spin texture has also been calculated and the results show that spin configuration at Q and Q’ have opposite signs (up and down, respectively) indicating that the valley couple occurs on the heterointerface. Our results suggest that WS2/CoO(111) is a promising candidate for valleytronic applications.