First-principles investigation of a new 2D magnetic crystal: Ferromagnetic ordering and intrinsic half-metallicity.

Abstract

The development of two-dimensional (2D) magnetic materials with half-metallic characteristics is of great interest because of their promising applications in spintronic devices with high circuit integration density and low energy consumption. Here, by using density functional theory calculations, ab initio molecular dynamics, and Monte Carlo simulation, we study the stability, electronic structure, and magnetic properties of a OsI3 monolayer, of which crystalline bulk is predicted to be a van der Waals layered ferromagnetic (FM) semiconductor. Our results reveal that the OsI3 monolayer can be easily exfoliated from the bulk phase with small cleavage energy and is energetically and thermodynamically stable at room temperature. Intrinsic half-metallicity with a wide bandgap and FM ordering with an estimated TC = 35 K are found for the OsI3 monolayer. Specifically, the FM ordering can be maintained under external biaxial strain from -2% to 5%. The in-plane magnetocrystalline anisotropy energy of the 2D OsI3 monolayer reaches up to 3.89 meV/OsI3, which is an order larger than that of most magnetic 2D materials such as the representative monolayer CrI3. The excellent magnetic features of the OsI3 monolayer therefore render it a promising 2D candidate for spintronic applications.