Computing accurate surface energies and the importance of electron self-energy in metal/metal-oxide adhesion

Abstract

Starting with density functional theory (DFT) results, we correct surface energies using a jellium model as applied to surface electron densities obtained from the first principles calculations. We apply these results to the computed work of adhesion for Pd(1 1 1) to α-Al 2O 3(0 0 0 1). Here polarization bonding dominates at the interface and is well described by DFT, but the surface energies of both the metal and the oxide have substantial errors due to electron self-exchange and self-correlation. 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, 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.