Defects engineering monolayer MoSe2 magnetic states for 2D spintronic device

摘要

The effects of vacancy and antisite defects, such as V-Mo, V(Mo2 )far, V-Mo2 close, V-Se , V-Se2 close, V-MoSe3, V-MoSe6 and Mo-Se2 on the electronic structure and magnetic properties of monolayer MoSe2 were systematically investigated using the density functional theory calculation. The theoretical results indicate that the single Mo vacancy (V-Mo ) induces a large magnetic moment of 3.939 mu(Beta) and shows magnetic halfmetallicity due to the Se unsaturated dangling bond around the Mo vacancies. Effective n-type doping can be achieved by the creation of Se vacancy (V-Se and V-Se2 ). However, the Se vacancy doped systems are nonmagnetic due to the formation of Mo-Mo metallic bonds around the Se vacancies, which results in the disappearance of Mo unsaturated dangling bonds. The V-MoSe3 and V-MoSe6 complex defects as well as Mo-Se2 antisite defect have high formation energy of defects. The V-MoSe3 remains nonmagnetic. However, the V-MoSe6 and Mo-Se2 defects induce a magnetic moment of 5.74 mu(Beta) and 1.92 mu(Beta), respectively, which originates from the unpaired 4d electrons between the nearest-neighbor Mo atoms. These results show that the vacancies can engineer the electronic structure and magnetic properties of monolayer MoSe2, which makes it become novel candidates for photo-catalysis, photoluminescence and spintronic devices. (C) 2018 Elsevier B.V. All rights reserved.