Two-dimensional ferromagnetic semiconductor VBr3 with tunable anisotropy

Abstract

Two-dimensional (2D) ferromagnets (FMs) have attracted widespread attention due to their prospects in spintronic applications. Here we explore the electronic structure and magnetic properties of the bulk and monolayer of VBr3 in the honeycomb lattice, using first-principles calculations, crystal field level analyses, and Monte Carlo simulations. Our results show that VBr3 bulk has the e ′ g 2 (S=1) ground state and possesses a small orbital moment and weak magnetic anisotropy favoring in-plane. Those results well explain the recent experiments. More interestingly, we find that a tensile strain on the semiconducting VBr3 monolayer tunes the ground state into a1g 1 e ′ g 1 and thus produces a large orbital moment and a strong out-of-plane anisotropy. Then, the significantly enhanced FM superexchange and single ion anisotropy (SIA) would raise TC from 20 K for the bare VBr3 monolayer to 100-115 K under a 2.5%-5% strain. Therefore, VBr3 would be a promising 2D FM semiconductor with a tunable anisotropy.