We report a giant thermoelectric figure of merit ZT (up to 6 at 1100 K) in n-doped lanthanum oxysulphate LaSO. Thermoelectric coefficients are computed from ab initio bands within Bloch-Boltzmann theory in an energy-, chemical potential- and temperature-dependent relaxation time approximation. The lattice thermal conductivity is estimated from a model employing the ab initio phonon and Gr\"uneisen-parameter spectrum. The main source of the large ZT is the significant power factor which correlates with a large band complexity factor. We also suggest a possible n-type dopant for the material based on ab initio calculations.
@article{arxiv.2111.13874,
title = {Giant thermoelectric figure of merit in multivalley high-complexity-factor LaSO},
author = {Roberta Farris and Francesco Ricci and Giulio Casu and Diana Dahliah and Geoffroy Hautier and Gian-Marco Rignanese and Vincenzo Fiorentini},
journal= {arXiv preprint arXiv:2111.13874},
year = {2021}
}