First-principles prediction of Structural Stability and Thermoelectric Properties of SrGaSnH

TL;DR

This study uses first-principles calculations to evaluate the structural stability and thermoelectric properties of SrGaSnH, an earth-abundant, non-toxic material, revealing its potential for eco-friendly thermoelectric applications.

Contribution

It provides the first detailed theoretical analysis of SrGaSnH’s stability and thermoelectric performance, highlighting its potential as a sustainable thermoelectric material.

Findings

SrGaSnH is structurally stable with an indirect bandgap of 0.63 eV.

High lattice thermal conductivity (~10.5 W/m·K) limits ZT.

Maximum ZT values are around 1 at 700 K, indicating promising thermoelectric performance.

Abstract

Thermoelectric materials based on earth-abundant and non-toxic elements are very useful in cost-effective and eco-friendly waste heat management systems. The constituents of SrGaSnH are earth-abundant and non-toxic, thus we have chosen SrSnGaH to study its structural stability and thermoelectric properties by using DFT, DFPT, and semi-classical Boltzmann transport theory. Our elastic and phonons calculations show that the compound has good structural stability. The electronic structure calculation discloses that it is an indirect bandgap (0.63 eV by mBJ+SOC) semiconductor. Light band hole effective mass leads to higher electrical conductivity along x-axis than that of along z-axis. On the other side, the weak phonon scattering leads to high lattice thermal conductivity ~10.5 W m-1K-1 at 300 K. Although the power factor (PF) is very high along the x-axis (above 10 mW m-1K-2 at 300 K), such large kl dramatically reduces ZT. The maximum values of in-plane and cross-plane ZT are ~1 (n-type), 0.8 (p-type) and 0.6 (n-type), (0.2 p-type) at 700 K, respectively. The present study has revealed that this compound has strong potential in eco-friendly TE applications.