A binary embedded-atom method potential was optimized for Cu on Ag(111) by fitting to ab initio data. The fitting database consists of density functional theory calculations of Cu monomers and dimers on Ag(111), specifically their relative energies, adatom heights, and dimer separations. Starting from the Mishin Cu–Ag embedded-atom method potential, the Cu–Ag pair potential was first modified to match the fcc/hcp site energy difference then include Cu–Cu pair potential optimization for the entire database. The potential generated from this optimization method gives better agreement to density functional theory calculations of Cu monomers, dimers, and trimers than previous embedded-atom methods as well as a SEAM optimized potential. In trimer calculations, the optimized potential produces the density functional theory relative energy between face-centered cubic and hexagonal close-packed trimers, though a different ground state was predicted. The optimized potential was used to calculate diffusion barriers for Cu monomers, dimers, and trimers. The predicted monomer barrier was the same as density functional theory, while experimental barriers for monomers and dimers were lower than predicted here. The difference, as compared with experiment, was attributed to the over-estimation of surface adsorption energies by density functional theory and a simple correction was presented. The results show that this optimization method was suitable for other hetero-epitaxial systems; and that the optimized Cu–Ag embedded-atom method could be applied in the study of larger Cu islands on Ag(111).

Cu/Ag EAM Potential Optimized for Heteroepitaxial Diffusion from ab initio Data. H.H.Wu, D.R.Trinkle: Computational Materials Science, 2009, 47[2], 577-83