Protected Valley-polarized Quantum anomalous Hall Effect in defected tungsten disulfide monolayer

Valley, a new degree of freedom of electron in addition to charge and spin, offer another anomalous Hall effect for quantum systems. So far, only small valley splitting has been observed in experiment. Therefore, it is important to find some new materials with large valley splitting and high thermal stability for the potential widespread applications. By using first-principles calculations, we discovered defected tungsten disulfide monolayer with 3d metal adsorption have valley splitting large than 50meV. Strikingly, the case with Fe adatoms has tunable large magnetic anisotropy which offers possible to observe the valley splitting at a high temperature, and a valley-polarized anomalous Hall current will be generated in the presence of an in-plane electric field. Furthermore, a protective environment can be formed for these novel characters by covering a hexagonal BN layer. Our findings offer a potential object for observing valley Hall effect and realizing novel valley-contrasting physics.