Favorable half-Heusler structure of synthesized TiCoSb alloy: a theoretical and experimental study

Abstract

The most favorable structure of the synthesized TiCoSb half-Heusler alloy is explored theoretically and experimentally, and the best structure for thermoelectric conversion is reported. Rietveld refinement of the X-ray diffraction data employing four probable structures of the HH alloy is performed to obtain the best fit and identify the crystallized structure. However, microstructural characterization is performed using the energy dispersive X-ray spectroscopy and transmission electron microscopy to reveal the stoichiometry and Bragg reflection planes of the synthesized polycrystalline lattice structure of TiCoSb HH alloy. Theoretical investigation is performed by implementing the first principle calculation using the Full Potential Linearized Augmented Plane Wave method in the Quantum Espresso software package. The most probable structure is explored by estimating the minimum energy at equilibrium volume and electronic structure of the TiCoSb half-Heusler alloy of the four probable structures considered. The theoretical and experimental data are corroborated, and the most probable structure is identified for the crystallized TiCoSb HH alloy. The thermoelectric properties of the most probable structure are estimated.