Unraveling the microscopic origin of out of plane magnetic anisotropy in VI3

Abstract

Intrinsic two-dimensional (2D) ferromagnetic (FM) semiconductors have attracted extensive attentions for their potential applications in next-generation spintronics devices. In recent years, the van der Waals material VI3 has been experimentally found to be an intrinsic FM semiconductor. However, the electronic structure of the VI3 is not fully understood. To reveal why the VI3 is a ferromagnetic semiconductor with strong out-of-plane anisotropy, we systematically studied the electronic structure of the monolayer VI3. Our results confirm that the monolayer VI3 is a Mott insulator, and d2 electrons occupy ag and egπ+ orbitals. The half-metallic state is a metastable state with a total energy 0.7 eV higher than the ferromagnetic Mott insulating state. Furthermore, our study confirmed that the VI3 exhibits the out-of-plane magnetic anisotropy, which originates from d2 electrons occupying low-lying ag and egπ+ orbitals. Since the orbital angular momentum of the egπ+ state is not completely quenched, the VI3 has the out-of-plane anisotropy under interplay between the spin-orbit coupling and crystal field. Our study provides valuable guidance for the design of 2D magnetic materials with pronounced out-of-plane anisotropy.