We propose an approach to calculate the anharmonic part of the volumetric-strain and temperature dependent free energy of a crystal. The method strikes an effective balance between accuracy and computational efficiency, showing a ×10 speed-up on comparable free energy approaches at the level of density functional theory, with average errors less than 1 meV/atom. As a demonstration we make new predictions on the thermodynamics of substoichiometric ZrCx, including vacancy concentration and heat capacity.
@article{arxiv.1904.02494,
title = {A fast anharmonic free energy method with an application to vacancies in ZrC},
author = {Thomas A. Mellan and Andrew I. Duff and Blazej Grabowski and Michael W. Finnis},
journal= {arXiv preprint arXiv:1904.02494},
year = {2019}
}