Protected giant magnetic anisotropy in two-dimensional materials: Transition-metal adatoms on defected tungsten disulfide monolayer

Giant magnetic anisotropy energies (MAEs), especially in systems that are well protected, are needed for the development of nanomagnetic devices. By using the first-principles calculations, we systematically investigated the structural and magnetic properties of 3d and 5d transition metal adatoms on a defected tungsten disulfide monolayer. Among these two-dimensional materials, Ir@D-WS2 and Os@D-WS2 possess extremely large MAEs (up to ∼40 meV/adatom). Furthermore, their large MAEs may sustain when we put a layer of graphene on top to protect them. The MAE of Os@D-WS2 can be tuned in a large range, up to 300%, by applying an external electric field of 0.5 V/Å. In addition, these systems exhibit unusual valley dependent topological features such as nontrivial band gaps and large Berry curvatures, and they hence are promising for technological innovations.