Metal Surface Energy: Persistent Cancellation of Short-Range Correlation Effects beyond the Random-Phase Approximation

TL;DR

This paper investigates the impact of short-range correlation effects on metal surface energies, finding that these effects largely cancel out, leading to results close to the random-phase approximation and indicating small errors in local-density approximations.

Contribution

It demonstrates that short-range correlation effects on surface formation energy contributions cancel out, validating the accuracy of the RPA and local-density approximation for metal surfaces.

Findings

Short-range correlation effects cancel each other at metal surfaces.

Calculated surface energies closely match RPA results.

Local-density approximation errors are minimal.

Abstract

The role that non-local short-range correlation plays at metal surfaces is investigated by analyzing the correlation surface energy into contributions from dynamical density fluctuations of various two-dimensional wave vectors. Although short-range correlation is known to yield considerable correction to the ground-state energy of both uniform and non-uniform systems, short-range correlation effects on intermediate and short-wavelength contributions to the surface formation energy are found to compensate one another. As a result, our calculated surface energies, which are based on a non-local exchange-correlation kernel that provides accurate total energies of a uniform electron gas, are found to be very close to those obtained in the random-phase approximation and support the conclusion that the error introduced by the local-density approximation is small.