New two-dimensional Mn-based MXenes with room-temperature ferromagnetism and half-metallicity

Abstract

Magnetic properties of Mn₂CT₂ (T = F, Cl, OH, O, and H) MXenes are reported based on a computational investigation. While other two dimensional Mn₂CT₂ MXenes become non-magnetic upon symmetrical functionalization of their surfaces, the Mn₂C MXene functionalized with a functional group bearing formal charge −1 (F, Cl, and OH) retains the ferromagnetic ground state upon functionalization. Based on density functional theory calculations and Monte Carlo simulations the Mn₂CF₂ MXene is predicted to be an intrinsic half-metal with high Curie temperature (520 K), wide half-metallic gap (0.9 eV) and a sizable magnetic anisotropy (24 μeV). These magnetic properties make the Mn₂CF₂ MXene an optimal material for applications in spintronics. Different surface functional groups lead to either quantitative (Cl and OH) or qualitative (O and H) changes in Mn₂CT₂ magnetic properties. It is proposed that Mn₂CT₂ MXenes can be prepared experimentally from the already existing parent Mn₂GaC MAX phase by exfoliation techniques.