Electronic Structure and Thermoelectric Properties of Half-Heusler Alloys NiTZ

TL;DR

This study investigates the electronic and thermoelectric properties of NiTZ half-Heusler alloys using density functional theory, revealing their potential as efficient thermoelectric materials with promising ZT values at high temperatures.

Contribution

The paper provides a comprehensive theoretical analysis of NiTZ alloys' thermoelectric properties, highlighting their potential for high-temperature applications and suggesting doping strategies to enhance performance.

Findings

NiTZ alloys are indirect band gap semiconductors.

Lattice thermal conductivity is comparable to leading thermoelectric materials.

ZT values at 1200 K are 0.46, 0.35, and 0.29 for NiScP, NiScAs, and NiScSb, respectively.

Abstract

We have investigated the electronic and thermoelectric properties of half-Heusler alloys NiTZ (T = Sc, and Ti; Z = P, As, Sn, and Sb) having 18 valence electron. Calculations are performed by means of density functional theory and Boltzmann transport equation with constant relaxation time approximation, validated by NiTiSn. The chosen half-Heuslers are found to be an indirect band gap semiconductor, and the lattice thermal conductivity is comparable with the state-of-the-art thermoelectric materials. The estimated power factor for NiScP, NiScAs, and NiScSb reveals that their thermoelectric performance can be enhanced by appropriate doping rate. The value of ZT found for NiScP, NiScAs, and NiScSb are 0.46, 0.35, and 0.29, respectively at 1200 K.