A First Principle Study of Half-Heusler Compounds CrTiZ (Z = P, As)

Half-Heusler compounds CrTiZ (Z = P, As) are studied in the framework of Density Functional Theory (DFT). Structural, mechanical, elastic, electronic, magnetic, and optical properties are derived using first principles. The full-potential linearized augmented plane wave (FP-LAPW) method is used for these investigations as implemented in the WIEN2k simulation package. We have found that the equilibrium lattice parameters are in the range 5.5–5.9 Å. Small band gaps of 0.5–0.6 eV in the minority spin-down states are observed. On the other hand, in the majority spin-up states, there is no band gap. Hence, the compounds are of half-metallic nature, having 100 % polarization at Fermi level. Comparatively, a higher total magnetic moment of ∼ 3μ_B is found for both the compounds. Furthermore, optical properties are derived using dielectric function. Reflectivity, refractive index, conductivity and absorption coefficient are calculated. It is revealed from the imaginary part of the dielectric function that the compounds are optically metallic.