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=3×1020cm−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.
@article{arxiv.2008.06455,
title = {First-Principles Study of Strain Effect on Thermoelectric Properties of LaP and LaAs},
author = {Chia-Min Lin and Wei-Chih Chen and Cheng-Chien Chen},
journal= {arXiv preprint arXiv:2008.06455},
year = {2021}
}