Accurate semilocal density functional for condensed matter physics and quantum chemistry

TL;DR

This paper introduces a new semilocal density functional derived from an exchange hole based on the density matrix expansion, achieving high accuracy across molecules, solids, and surfaces, and improving upon recent nonempirical functionals.

Contribution

The authors develop a novel semilocal exchange-correlation functional derived from a localized exchange hole, enhancing accuracy in condensed matter physics and quantum chemistry applications.

Findings

Achieves remarkable accuracy for diverse molecular and solid-state properties.

Substantially improves upon recent nonempirical density functionals.

Provides a physically appealing and practically useful approach for functional development.

Abstract

Most density functionals have been developed by imposing the known exact constraints on the exchange-correlation energy, or by a fit to a set of properties of selected systems, or by both. However, accurate modeling of the conventional exchange hole presents a great challenge, due to the delocalization of the hole. Making use of the property that the hole can be made localized under a general coordinate transformation, here we derive an exchange hole from the density matrix expansion, while the correlation part is obtained by imposing the low-density limit constraint. From the hole, a semilocal exchange-correlation functional is calculated. Our comprehensive test shows that this functional can achieve remarkable accuracy for diverse properties of molecules, solids and solid surfaces, substantially improving upon the nonempirical functionals proposed in recent years. Accurate semilocal functionals based on their associated holes are physically appealing and practically useful for developing nonlocal functionals.