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

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 mu eV). 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.