Two dimensional Janus Ti-trihalide monolayers with half-metallic characteristics, Mott insulator properties and tunable magnetic anisotropy

Abstract

Two-dimensional (2D) ferromagnets have attracted widespread attention due to their prospects in spintronic applications. Here, the electronic and magnetic properties of Janus Ti₂X₃Y₃ (X, Y = I, Br, Cl) monolayers are studied. Two types of orbital splitting may exist in the Ti₂X₃Y₃ monolayers, corresponding to the semiconducting and half-metallic states. The ground state is a ferromagnetic (FM) semiconductor with in-plane magnetic anisotropy (IMA). The weak FM interactions are mainly mediated by the halogen atoms, with a predicted Curie temperature (T_C) of about 10 K. Ti₂X₃Y₃ monolayers are soft 2D materials with a Young's modulus of below 27.5 N m⁻¹, and the band gap can be adjusted by in-plane biaxial strain. The magnetic anisotropy of the monolayers is mainly contributed by the heavy halogen elements, and polarization substitution and biaxial strain will not change the easy magnetization orientation of the monolayers. It is expected that our design may enrich the 2D functional materials, which may find versatile applications.