Non-local exchange-correlation potential at a metal surface from many-body perturbation theory

• Published in: Vacuum 1990, Vol.41 (1), p.533-534
• Main Authors: Eguiluz, A.G., Hanke, W, Gies, P, Heinrichsmeier, M
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Metals. Metallurgy; Physics; Surface and interface electron states
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/0042-207X(90)90407-P

We report a first-principles evaluation of the exchange-correlation potential (V XC ) at a metal surface. An integral equation relating (V XC ) and the non-local electron self-energy (Σ XC ) is solved numerically for a free-electron metal surface, with use of a static approximation for Σ XC . The strongly-inhomogeneous nature of the electron density profile at the surface is treated exactly, i.e. without invoking the usual local density approximation. Our result for V XC has the correct image-like asymptotic behavior; it derives implicitly from a non-local exchange-correlation energy functional. We study the effect of non-locality on the position of the effective image plane (z O) from an analysis of the image tail of V XC and also from linear-response theory. The difference in the values of z O obtained by both methods for low metallic densities is attributed to electron overlap effects. We also discuss the effects of V XC on image-potential induced surface states.