Large magnetic anisotropy and enhanced Curie temperature in two-dimensional MnTe2 coupled with β-phase group-VA semiconductor monolayers

Abstract

Promoting the Curie temperature (T_C) and tunning the magnetocrystalline anisotropy energy (MAE) have been key issues with two-dimensional (2D) ferromagnetic (FM) materials. Here, the structural and magnetic properties of MnTe₂/X (X = As, Sb and Bi) heterostructures are investigated through first-principles calculations. We reveal that monolayer MnTe₂ weakly interacts with monolayer As or Sb through van der Waals (vdW) forces, but has strong covalent bonds with monolayer Bi, indicated by Bi–Te bond formation. The coupling of MnTe₂ with these β-phase group-VA semiconductor monolayers substantially modulates MAE, with MnTe₂/As showing a shift to in-plane easy magnetization, and MnTe₂/Sb exhibiting a large perpendicular MAE of 4.13 meV per cell. The formation of vdW heterostructures influence on Te spin–orbit coupling matrix elements markedly governs MAE. MnTe₂/Bi also has an in-plane MAE, contributed by both Te and Bi atoms. Additionally, coupling MnTe₂ with X significantly affects magnetic interactions. It is worth noting that the T_C of MnTe₂/Sb reaches 233.2 K, significantly larger than that of pure MnTe₂. A large perpendicular MAE and a heightened T_C makes MnTe₂/Sb desired candidates for next-generation spintronic applications. Our work provides a way to modulate the magnetic properties of 2D FM materials.