Valley and spin splitting in monolayer TX2/antiferromagnetic MnO (T = Mo, W; X = S, Se) van der Waals heterostructures

Abstract

The electronic structure of monolayer MoS2, WS2, MoSe2 and WSe2 on top of antiferromagnetic MnO(1 1 1) is investigated systematically by first-principles calculations. It is found that termination of the MnO substrate can switch the spin splitting of monolayer MoS2, WS2, MoSe2 and WSe2. The spin splitting of MoS2/MnO for six possible interface configurations is varied from 24 to 291 meV for the K point, and 18 to 253 meV for the Kʹ point. The pattern of stacking also induces p - or n-type doping of MoS2, revealing that the conductivity of the heterostructures could be tuned by stacking on MnO. In addition, we also calculate electronic structures of WS2/MnO, MoSe2/MnO and WSe2/MnO heterostructures in the Mn-terminated (III) configuration, and find that the spin splitting at the K point is 553, 324 and 481 meV, and 215, 9 and 284 meV for the Kʹ point, respectively. Furthermore, the time-reversal symmetry is broken by the stacking on MnO that leads to the valley polarization. The valley splitting of MoS2/MnO, WS2/MnO, MoSe2/MnO and WSe2/MnO is 161, 193, 171 and 125 meV in the Mn-terminated (III) configuration. The results present a new type of novel heterostructure that has potential applications in spintronic and valleytronic devices.