Two dimensional MoF₃ and Janus Mo₂F₃X₃(X = Cl, Br, I): intrinsic ferromagnetic semiconductor, large perpendicular magnetic anisotropy, and hole-induced room-temperature ferromagnetism

Abstract Two-dimensional (2D) ferromagnetic (FM) semiconductors with high Curie temperature ( T c ) and large perpendicular magnetic anisotropy (PMA) are promising for developing next-generation magnetic storage devices. In this work, we investigated the structural, electronic, and magnetic properties of MoF 3 and Janus Mo 2 F 3 X 3 ( X = Cl, Br, I) monolayers by first-principles methods. These materials are 2D FM semiconductors with large PMA and half-semiconducting character as both VBM and CBM belonging to the spin-up channel. Biaxial strain can modulate band gap, reverse easy magnetization axis, and induce magnetic phase transitions in MoF 3 monolayer and its Janus structures. Compared to MoF 3 monolayers, Janus Mo 2 F 3 X 3 monolayers can preserve the structural ability and the FM ground state over a wider range of strain. The magnetic anisotropy energies (MAEs) of these 2D materials can be enhanced to greater than 1 meV/Mo by tensile strains. Intrinsic T c of MoF 3 monolayer and its Janus structures are less than 110 K and are insensitive to strain. However, hole doping with a feasible concentration can achieve a room-temperature half-metallicity in these 2D materials. The required hole concentration is lower in Janus Mo 2 F 3 X 3 monolayers than MoF 3 monolayer. Our results indicate that MoF 3 and Janus Mo 2 F 3 X 3 ( X = Cl, Br, I) monolayers are promising candidates for 2D spintronic applications and will stimulate experimental and theoretical broad studies.