MD simulation of growth of Pd on Cu (111) and Cu on Pd (1 1 1) substrates

We develop the second nearest-neighbor modified embedded atom method to describe the Cu/Pd system. The potential parameters are determined by fitting cohesive energy, lattice parameter, and elastic constants of the CsCl-type CuPd obtained by first principles calculation. We simulate the deposition of Cu-Pd bilayer films by depositing either Pd on Cu (1 1 1) substrates or Cu on Pd (1 1 1) substrates using different incident energies, followed by an annealing to relieve internal stress. We find that the developed potential can describe the fundamental physical and mechanical properties of both pure Pd and Cu as well as their alloys. It is found that the surface roughness decreases with the increase of incident energy. Twin structure is identified in the bilayers films, and the twin formation process is analyzed. The incident energy is found to affect the quality of the growth twins.