MnX (X = P, As) monolayers: a new type of two-dimensional intrinsic room temperature ferromagnetic half-metallic material with large magnetic anisotropy.

Recent experimentally demonstrated intrinsic two-dimensional (2D) magnetism has sparked intense interest for advanced spintronic applications. However, the rather low Curie temperature and small magnetic anisotropic energy (MAE) greatly limit their application scope. Here, by using density functional theory calculations, we predict a series of stable 2D MnX (X = P, As, Sb) monolayers, among which MnP and MnAs monolayers exhibit intrinsic ferromagnetic (FM) ordering and considerably large MAEs of 166 and 281 μeV per Mn atom, respectively. More interestingly, the 2D MnP and MnAs monolayers exhibit highly desired half-metallicity with wide spin gaps of about 3 eV. Monte Carlo simulations suggest markedly high Curie temperatures of MnP and MnAs monolayers, ∼495 K and 711 K, respectively. Besides, these monolayers are the lowest energy structures in the 2D search space with excellent dynamic and thermal stabilities. A viable experimental synthesis route is also proposed to produce MnX monolayers via the selective chemical etching method. The outstanding attributes of MnP and MnAs monolayers would substantially broaden the applicability of 2D magnetism for a wide range of applications.