Corrected effective-medium study of metal-surface relaxation

Abstract

We have studied the relaxation of some metal surfaces using a corrected effective-medium (CEM) theory. CEM is a non-self-consistent, density-functional technique. The interaction energy is calculated as a sum of three components: the embedding energy of an atom in jellium, the interatomic Coulomb energy, and the kinetic exchange-correlation energy. A theoretical procedure has been developed to determine the embedding energies via linear-muffin-tin-orbital calculations. This refinement of the theory is tested for surface energies and structures of some relaxed Al, Ni, Cu, Rh, Pd, and Ag surfaces. Comparisons are made to the embedded-atom method, the effective-medium technique, and a simpler version of CEM that is used in molecular-dynamics and Monte Carlo simulations. We present an in-depth analysis of the results, and discuss the physical basis of surface relaxation within CEM. Finally, we address the limitations inherent in calculations of metal-surface relaxation.