Strain-induced high Chern number topological insulator state in Fe- or V-decorated MoS2 monolayers

The electronic structure and topological state of an MoS2 monolayer decorated by iron or vanadium adatoms is investigated by first -principles calculations. It is shown that several Chern insulator phases occur in these samples in the presence of external strain or electric field. In particular, Chern number C = 2 is achieved by applying 6% biaxial tensile strain on the V -decorated MoS2 monolayer or 10% on the Fe -decorated one. On the other hand, the intrinsic C = 1 phase of the iron system is switched to the normal insulator phase under an electric field of 0.8 V/angstrom, while the vanadium system with intrinsic C = -1 state adopts a C = 1 state if the electric field reaches 0.7 V/angstrom. The induced band inversion may coincide with an abrupt increase of magnetization and a simultaneous change in the adatom adsorption height, or a magnetization decrement without displacement of the adatom. Our findings suggest that applying an in -plane biaxial tensile strain is a promising direction to search high Chern number states.