Surface energy of a bounded electron gas: Analysis of the accuracy of the local-density approximation via ab initio self-consistent-field calculations

TL;DR

This paper evaluates the surface energy of a simple metal using ab initio methods, comparing the local-density approximation's accuracy with more exact calculations, and finds the approximation introduces only a small error.

Contribution

It provides a quantitative assessment of the local-density approximation's accuracy for surface energy calculations using ab initio self-consistent-field methods.

Findings

The local-density approximation incurs a small error in surface energy estimates.

Exact treatment of electron density change at the surface improves accuracy.

Self-consistent inclusion of correlations enhances the reliability of the results.

Abstract

We report an ab initio evaluation of the surface energy of a simple metal, performed via a coupling-constant integration over the dynamical density-response function. The rapid rate of change of the electron density at the surface is treated exactly. Long-range correlations are treated self-consistently in the random-phase approximation; short range correlations are included in time-dependent local density-functional theory. Our results provide a numerical measure of the error introduced by the usual local-density approximation; this error is found to be small.