Abstract
Layered transition metal trihalide WI3 is a new candidate in the race for two-dimensional (2D) magnetic materials. We investigated the electronic band structure and magnetic anisotropy of its monolayer by applying an external electric field using first-principles calculations based on density functional theory. Our calculation predicted that the WI3 monolayer exhibits an antiferromagnetic (AFM) ground state with out-of-plane easy axis. The external electric field could not induce a transition from its antiferromagnetic to ferromagnetic ground state. Rather, its AFM ground state becomes more robust with the application of external perturbation (such as electric field). We found that WI3 is a semiconductor with an indirect electronic band gap of about 1.7 eV. The orbital-resolved band structure revealed that the valence band maximum and the conduction band minimum are mainly dominated by the d(x2-y2) and d(z2) orbitals of W, respectively. These two orbitals mainly contribute to the electronic transitions associated with the electronic band gap of the system. In addition, the application of an electric field tuned its band gap and induced a transition from semiconductor to metal at an electric field E = 1.0 V/angstrom due to the giant linear Stark effect. Based on mean field theory, we also predicted that the application of an electric field could tune the Ned temperature (T-N) from 40 K to an elevated temperature, which is critical for the working of spintronic devices. Our investigation also includes an in-depth orbital-resolved analysis of electric field-dependent magnetic anisotropy of the WI3 monolayer. We predicted that the magnetic anisotropy energy (MAE) of the system is dependent on the applied electric field. The orbital-resolved MAE study showed that, unlike the CrI3 monolayer, the major contribution to MAE arises from the transition metal element W.