Self-consistent density functional calculation of the image potential at a metalsurface

Abstract

It is well known that the exchange–correlation (XC) potential ata metal surface has an image-like asymptotic behaviour given by−1/4(z−z0),where z is the coordinate perpendicular to the surface. Using a suitable fully non-localfunctional prescription, we evaluate self-consistently the XC potential with the correctimage behaviour for simple jellium surfaces in the range of metallic densities. Thisallows a proper comparison between the corresponding image-plane position,z0, and other related quantities such as the centroid of an induced charge by anexternal perturbation. As a by-product, we assess the routinely used local densityapproximation when evaluating electron density profiles, work functions, andsurface energies by focusing on the XC effects included in the fully non-localdescription.