First-principle study of mechanical, optical and thermophysical properties of NiTiSn

In present work we have studied half-Heusler compound NiTiSn in perspective of optical, mechanical and thermophysical properties at high temperature and high pressure using density functional theory. We have calculated various dielectric properties viz absorption coefficients, optical conductivity, optical reflectivity and electron energy loss. We have also found high refractive index n(0) ≈ 5 of NiTiSn indicating highly denser medium for low energy waves. The calculated absorption coefficient and optical conductivity are in agreement with the experimental ones for optical device. The optical investigation of the compound shows high reflectivity in the UV region of the photon energy. The elastic properties are investigated in most stable structure of NiTiSn in order to ensure its mechanical applications. Our estimated values of Poisson ratio (n = 0.2735) and pughratio (B/G = 1.87) confirm the metallic nature of NiTiSn. Various thermophysical properties viz. Debye temperature, isothermal coefficients, heat capacity, entropy and volume have been studied at high temperature and high pressures which will upgrade its thermoelectric properties study. The thermophysical properties ensures the Debye T3 law and Dulong Petit limit of NiTiSn at high temperatures and high pressures.