To be presented at the Sandia National Laboratories Workshop on Quantum Mechanical Techniques: Exchange-Correlation Functionals in Density Functional Theory,

Albuquerque, NM, August 14-16, 2002

The Importance of Surface Self-Energy in

Metal/Metal-Oxide Adhesion

D. R. Jennison and A. E. Mattsson

Surface and Interface Sciences Department 1114

Sandia National Laboratories

Albuquerque, NM 87185-1415

Abstract

Starting with density functional theory (DFT) results, we correct the computed work of adhesion for Pd(111) to a-Al₂O₃(0001). Here polarization bonding dominates at the interface and is well described by DFT, but the surface energies of both the metal and the oxide must be altered for electron self-exchange and self-correlation. This is accomplished using a jellium model as applied to surface electron densities obtained from first principles calculations (see poster by A. E. Mattsson and T. R. Mattsson). We show that this correction is quite large for the generalized gradient approximation (GGA), thus explaining the difference between GGA results for metal/metal-oxide binding and those obtained by the local density approximation (LDA), where an accidental cancellation in errors produces better agreement with experiment. After the corrections, both methods produce results that are within the experimental error bars.

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.