Deorbitalized meta-GGA exchange-correlation functionals in solids

Abstract

A procedure for removing explicit orbital dependence from meta-generalized-gradient approximation (mGGA) exchange-correlation functionals by converting them into Laplacian-dependent functionals recently was developed by us and shown to be successful in molecules. It uses an approximate kinetic energy density functional (KEDF) parametrized to Kohn-Sham results (not experimental data) on a small training set. Here we present extensive validation calculations on periodic solids that demonstrate that the same deorbitalization with the same parametrization also is successful for those extended systems. Because of the number of stringent constraints used in its construction and its recent prominence, our focus is on the SCAN meta-GGA. Coded in \textsc{vasp}, the deorbitalized version, SCAN-L, can be as much as a factor of three faster than original SCAN, a potentially significant gain for large-scale ab initio molecular dynamics.