Half-Metallicity and Magnetic Anisotropy in Transition-Metal-Atom-Doped Graphitic Germanium Carbide (g-GeC) Monolayers

Ferromagnetic half-metallic materials with wide half-metallic gap, large magnetic anisotropy energy, and high Curie temperature have attracted much attention for their potential applications in spintronic devices. The electronic structure and magnetic properties of 3d, 4d, and Sd transition-metal-atom-(TM)-doped graphitic germanium carbide (g-GeC) monolayers have been systematically studied by first-principles calculations. The g-GeC monolayer doped with TMs has abundant properties of half-metals, metals, and semiconductors. Among them, the Cr, Mn, Fe, Co, Mo, and W atom-doped g-GeC monolayer shows half-metallic properties due to the hybridization of TMs-d and Ge/C-p orbitals, in which the spin-down channel is semiconducting with wide band gaps, i.e., 2.30, 2.19, 1.22, 1.00, 1.84, and 2.10 eV, respectively. Additionally, the Mn, Fe, Mo, and W atom-doped g-GeC monolayer shows perpendicular magnetic anisotropy (PMA), while the Co and Cr atoms show in-plane magnetic anisotropy. The PMA of W-atom-doped g-GeC monolayer is 3.46 mJ/m(2), which is attributed to the magnetic anisotropy contribution of W-(d(z)(2), d(xz)) and W-(d(yz), d(xz))orbitals coupling matrix elements. These results indicate that TM-doped g-GeC monolayers have potential applications in spintronic devices.