First-Principles Calculation of the Phonon and Thermoelectric Properties of NiZnSn Half Heusler Alloy

Umukoro JO, Omagbemi OG and Osafile OE

Published on: 2022-06-28

Abstract

The search for viable thermoelectric materials is on the front burner for researchers in material science due to the world energy crisis. Several materials have proved to be promising at both high and low-temperature regimes; however, to correctly predict the thermoelectric properties of a material, the relationship among the parameters of the dimensionless figure of merit needs to be understood and correctly analysed. In this work, we have adopted a first-principles method to investigate the structural, electronic, phonon, and transport properties of NiZrSn based on the density functional theory using the generalized gradient approximation implemented in the quantum espresso suite. The band gap, lattice constant and other structural and electronic property results obtained in this work compare well with experimental and theoretical results from previous work. Furthermore, we studied the phonon and transport properties of the alloy. The phonon dispersion and phonon density of states prove that NiZrSn is stable. The LO-TO splitting in the acoustic and optical phonon branches supports covalent and ionic bonding in the alloy. The thermoelectric properties with hole and electron doping and carrier concentrations suggest that NiZrSn will be a better thermoelectric material as an n-type semiconductor.