Ab Initio Investigations of Structural, Elastic, Mechanical, Electronic, Magnetic, and Optical Properties of Half-Heusler Compounds RhCrZ (Z = Si, Ge)

The first principle study of half-Heusler compounds RhCrZ (Z = Si, Ge) is performed in the framework of density functional theory (DFT). The compounds are found to have small band gap in the minority spin channel (spin-down). While the majority spin channel (spin-up) is metallic. Therefore, both compounds are half-metallic and 100 % spin polarized at Fermi level. Several properties including structural, mechanical, elastic, electronic, magnetic, and optical are computed using the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k simulation package. Equilibrium lattice constants for both compounds are found to be in the range 5.5–6.0 A. Elastic properties indicate the ductile nature of the compounds. The total magnetic moments for these compounds are approximately equal to 1μ B, i.e., MTot ≈ 1μ B. Hence, the compounds are weak ferromagnetic materials. We have calculated the complex dielectric function. Many optical properties including reflectivity, refractive index, conductivity, and absorption coefficients are obtained form dielectric function. Imaginary part of the dielectric functions shows that compounds are optically metallic and become transparent above 17 and 13 eV, respectively. It is also observed that compounds are more active in the infrared region.