Novel two-dimensional CrXB₂ (X=Cr, Ru) metal for high Néel temperature antiferromagnetic spintronics

Recently, the novel two-dimensional (2D) Cr₂B₂ sheet which exhibits metallic electronic property has attracted intense attention due to its diverse potential applications in batteries, sensors, electrocatalysis, spintronics, and superconductivity. In this work, we exploit the theoretical method by combining the density functional theory (DFT) calculations with Monte Carlo (MC) simulations to demonstrate the potential of tetragonal (tetra)Cr₂B₂, and CrRuB₂ phases for antiferromagnetic spintronics. Based on vibrations frequencies and finite-temperature molecular dynamics, we demonstrated that these sheets are dynamically and thermally stable. Among the different spin configurations, we have found that the ground state spin ordering of these structures is antiferromagnetic. The tetra-Cr₂B₂ exhibits a sizable magnetic anisotropy energy (MAE) of 101.63 μeV per Cr atom with out-of-plane magnetization whereas the MAE can be turned into an in-plane direction for the case of tetra- ​CrRuB₂ sheet. Monte Carlo simulations based on 2D Heisenberg model predicts a high Néel temperature (T_N) of tetra-Cr₂B₂ sheet up to 870 ​K. The results indicate the potential of tetra-Cr₂B₂ sheet for antiferromagnetic spintronics device applications.