First principles study of thermoelectric performance and efficiency of the ternary half-Heusler semiconductor LiMgAs: using GGA and meta-GGA methods

In this work, we used the first principles calculations to evaluate the power conversion efficiency of thermoelectric ternary half-Heusler alloy LiMgAs using GGA and meta-GGA methods. The results confirm the structural, chemical, and mechanical stability of LiMgAs in its \(\alpha \) $\alpha$ structural configuration. Using Boltzmann transport theory, we estimate the figure of merit (zT) by examining the electronic band structure around the Fermi level ( \(\hbox {E}_F\) ${\text{E}}_F$ ) energy and the Seebeck coefficient S. Our findings demonstrate excellent thermoelectric properties within the temperature range of 200–800 K for n and p doping regions. The high figure of merit (zT \( \sim \) $\sim$ 1 ) and the exceptional power efficiency ( \( \eta ^{GGA} = 13.57 \%\) ${\eta }^{\mathit{GGA}}=13.57\%$ and \( \eta ^{meta-GGA} = 15.70 \%\) ${\eta }^{meta-GGA}=15.70\%$ ) observed at the temperature difference of 600K indicate that the semiconductor LiMgAs is highly suitable for thermoelectric applications.