Crystal structure optimisation using an auxiliary equation of state
Abstract
Standard procedures for local crystal-structure optimisation involve numerous energy and force calculations. It is common to calculate an energy-volume curve, fitting an equation of state around the equilibrium cell volume. This is a computationally intensive process, in particular for low-symmetry crystal structures where each isochoric optimisation involves energy minimisation over many degrees of freedom. Such procedures can be prohibitive for non-local exchange-correlation functionals or other 'beyond' density functional theory electronic structure techniques, particularly where analytical gradients are not available. We present a simple approach for efficient optimisation of crystal structures based on a known equation of state. The equilibrium volume can be predicted from one single-point calculation, and refined with successive calculations if required. The approach is validated for PbS, PbTe, ZnS and ZnTe using nine density functionals, and applied to the quaternary semiconductor CuZnSnS and the magnetic metal-organic framework HKUST-1.
Cite
@article{arxiv.1507.08815,
title = {Crystal structure optimisation using an auxiliary equation of state},
author = {Adam J. Jackson and Jonathan M. Skelton and Christopher H. Hendon and Keith T. Butler and Aron Walsh},
journal= {arXiv preprint arXiv:1507.08815},
year = {2016}
}