Pursuit of thermoelectric properties in a novel Half Heusler compound: HfPtPb

TL;DR

This study investigates the structural, electronic, mechanical, and thermoelectric properties of the novel half Heusler compound HfPtPb, revealing its potential as an n-type semiconductor with promising thermoelectric performance at high temperatures.

Contribution

First comprehensive theoretical analysis of HfPtPb's stability, electronic structure, and thermoelectric properties using density functional theory and Boltzmann transport calculations.

Findings

HfPtPb is mechanically and dynamically stable.

It is a semiconductor with a 0.86 eV band gap.

Maximum thermoelectric figure of merit is 0.25 at 1000 K.

Abstract

We explore the structural, electronic, mechanical and thermoelectric properties of a new half Heusler compound, HfPtPb which is all metallic heavy element and has been recently been proposed to be stable [Nature Chem 7 (2015) 308]. In the present work, we employ density functional theory and semiclassical Boltzmann transport equations with constant relaxation time approximation. The mechanical properties such as Shear modulus, Young modulus, elastic constants, Poisson ratio, and shear anisotropy factor are investigated. The elastic and phonon properties reveal that this compound is mechanically and dynamically stable. Pugh and Frantsevich ratio demonstrates the ductile behavior and Shear anisotropic factor reflects the anisotropic nature of HfPtPb. The calculation of band structure predicts that this compound is semiconductor in nature with band gap 0.86 eV. The thermoelectric transport parameters such as Seebeck coefficient, electrical conductivity, and electronic thermal conductivity and lattice thermal conductivity have been calculated as a function of temperature. The highest value of Seebeck coefficient is obtained for n-type doping at optimal carrier concentration. We predict the maximum value of the figure of merit 0.25 at 1000 K. Our investigation suggests that this material is n-type semiconductor.