Prediction of Half-metallicity in the New Heusler CsYX2 (Y = Sc, Ti, V, Cr, and Mn; X = O and N) Compounds

Electronic structure calculations based on density functional theory of the new Heusler CsYX (2) (Y = Sc, Ti, V, Cr, and Mn; X = O and N) compounds were performed using the full-potential linearized augmented plane wave (FPLAPW) method. These compounds can be synthesized experimentally because of their negative formation energies. The CsYX (2) compounds were stable in an AlCu2Mn-type structure. CsScN2, CsTiO2, CsVN2, CsCrO2, and CsMnN2 compounds in the AlCu2Mn-type structure and CsScN2, CsTiO2, CsVO2, and CsMnO2 in an CuHg2Ti-type structure were half-metallic (HM) feromagnets. CsVO2 in the AlCu2Mn-type structure was a spin-gap less semiconductor. The origin of half-metallicity for CsCrO2 was verified using the partial density of states. The Slater-Pauling rules were used to determine the total magnetic moments of the HM CsYX (2) compounds. Furthermore, CsYX (2)-combined alloys had the widest regions of half-metallictiy in comparison with the Heusler alloys including transition metals, indicating that they may be promising materials for spintronic applications.