Restoring the density-gradient expansion for exchange in solids and surfaces

TL;DR

This paper introduces PBEsol, a revised GGA functional that restores the gradient expansion for exchange, significantly improving the accuracy of density functional calculations for solids and surfaces.

Contribution

The paper presents PBEsol, a new GGA functional that corrects the exchange gradient expansion bias in previous functionals, enhancing predictions for densely-packed solids and their surfaces.

Findings

PBEsol improves equilibrium properties of solids.

It provides better surface energy predictions.

The functional aligns closely with first-principles gradient expansion.

Abstract

Successful modern generalized gradient approximations (GGA's) are biased toward atomic energies. Restoration of the first-principles gradient expansion for exchange over a wide range of density gradients eliminates this bias. We introduce PBEsol, a revised Perdew-Burke-Ernzerhof GGA that improves equilibrium properties of densely-packed solids and their surfaces.