Vacancy defects in the vertical heterostructures of graphene and MoS2

Van der Waals (vdW) heterostructures of two-dimensional materials have attracted significant attention owing to their potential applications in electronics, optics, and catalysis. In this study, we investigated the energetics and electronic properties of vacancy defects in the vdW heterostructures of graphene and MoS2, based on first-principles density functional theory calculations. The effects of the interlayer interactions modify the atomic and electronic configurations of the defects substantially. As a result, the formation enthalpy of the C vacancies decreases by 0.06-0.54 eV, while that of the S vacancies increases by 0.36-0.53 eV. Interestingly, in the hetemstructure, the graphene layer with the C vacancy has a non-planar antiferromagnetic ground structure, which can be attributed to the effects of charge redistribution. In contrast, a competing ferromagnetic state has a planar graphene structure.