First-Principles Study of Ferromagnetic K_xCa_1−xN Novel Alloy

We report a first-principles investigation of electronic and magnetic properties of K_xCa_1−xN novel alloy. Results on total energy calculations confirm a ferromagnetic order for all K concentration with a total magnetic moment ranging from 1 to 2μ_B per cation. As for the parent compounds, CaN and KN, the origin of magnetism arises from the polarization of the nitrogen p-orbitals. The variation of the lattice constant as function with K composition exhibits a deviation from the Vegard's law. From the spin-polarized calculations, we show that the half-metallic gap increase with K composition, whereas energy band gap in the semiconducting spin part remains constant around 3 eV.