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arXiv · 2008.06455

First-Principles Study of Strain Effect on Thermoelectric Properties of LaP and LaAs

Chia-Min Lin·Wei-Chih Chen·Cheng-Chien Chen
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Abstract

Rare-earth monopnictides have attracted much attention due to their unusual electronic and topological properties for potential device applications. Here, we study rock-salt structured lanthanum monopnictides LaX (X = P, As) by density functional theory (DFT) simulations. We show systematically that a meta-GGA functional combined with scissor correction can efficiently and accurately compute electronic structures on a fine DFT $k$-grid, which is necessary for converging thermoelectric calculations. We also show that strain engineering can effectively improve thermoelectric performance. Under the optimal condition of 2% tensile strain and carrier concentration $n=3\times10^{20}~\textrm{cm}^{-3}$, LaP at temperature 1200 K can achieve a figure of merit $ZT$ value $>2$, which is enhanced by 90% compared to the unstrained value. With carrier doping and strain engineering, lanthanum monopnictides thereby could be promising high-temperature thermoelectric materials.

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Chia-Min Lin, Wei-Chih Chen, Cheng-Chien Chen. 2020-08-14. First-Principles Study of Strain Effect on Thermoelectric Properties of LaP and LaAs. https://doi.org/10.1039/d1cp02871e

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