Predicting MnB6 monolayer with room temperature ferromagnetism and high magnetic anisotropy

Searching for two-dimensional (2D) magnetic materials with high critical temperature and intrinsic magnetism have attracted significant research interests recently. By using swarm-intelligence structure search and first-principles calculations, we predict two low-energy MnB6 monolayers, namely MnB6-I and MnB6-II, with high stabilities and intriguing electronic and magnetic properties. Specifically, the phonon spectrum and ab initio molecular dynamics simulations indicate the two sheets are dynamically and thermally stable. The MnB6-I and MnB6-II layers are both metallic with ferromagnetic (FM) and antiferromagnetic (AFM) ground state, respectively. When spin-orbital coupling is considered, the type-II Dirac points and a sizable magnetocrystalline anisotropy energy (938 μeV per Mn atom) can be found in the MnB6-I sheet. The Monte Carlo simulation based on the Heisenberg model suggests the Curie temperature for MnB6-I sheet is up to 470 K, which is above room temperature. The superior electronic and magnetic properties of the MnB6 monolayers render them promising candidates for spintronic applications.