Predicting MnB6 monolayer with room temperature ferromagnetism and high magnetic anisotropy

Abstract

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 MnB 6 monolayers, namely MnB 6 -I and MnB 6 -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 MnB 6 -I and MnB 6 -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 μ eV per Mn atom) can be found in the MnB 6 -I sheet. The Monte Carlo simulation based on the Heisenberg model suggests the Curie temperature for MnB 6 -I sheet is up to 470 K, which is above room temperature. The superior electronic and magnetic properties of the MnB 6 monolayers render them promising candidates for spintronic applications. • Two stable phases of MnB 6 monolayers were predicted with ferromagnetic and antiferromagnetic ground states. • The calculated Curie temperature for MnB 6 -I sheet is up to 470 K, which is above room temperature. • The calculated Néel temperature for MnB 6 -II sheet is 180 K, higher than many reported antiferromagnetic materials. • When spin-orbital coupling is considered, MnB 6 -I sheet shows type-II Dirac points and a sizable magnetic anisotropy energy.