First principles study of 2D half-metallic ferromagnetism in Janus Mn2XSb (X = As, P) monolayers

Abstract

Two-dimensional (2D) intrinsic magnetic materials have attracted much attention because of their fascinating physical properties. However, low Curie temperature TC and small magnetic anisotropy energy (MAE) limit their application prospects. Based on the density functional theory, we predict that Janus Mn2AsSb and Mn2PSb monolayers are 2D intrinsic ferromagnetic half-metals. Monte Carlo simulations suggest that the TC values of these monolayers are about 385 and 334 K, respectively. The Mn2AsSb and Mn2PSb monolayers exhibit large MAEs of 415.2 and 450.6 μeV per Mn, respectively. Their ferromagnetism is robust against biaxial strain in the range from −10% to 10%. An energy band calculation with the Heyd–Scuseria–Ernzerhof (HES06) functional indicates that the half-metallic spin bandgaps are about 1.00 and 0.81 eV and the bandgaps on the spin-down channel are 2.67 and 2.53 eV for Mn2AsSb and Mn2PSb monolayers, respectively. These exciting electronic and magnetic properties make Janus Mn2XSb (X = As, P) monolayers promising candidate materials for 2D spintronic devices.