Structure and dynamics of ultra-thin silver and copper films on palladium(111)

have studied the structure and growth dynamics of ultrathin films of Ag and Cu on Pd(111). Both systems are comprised of an fcc film on an fcc substrate. Moreover, Ag and Cu are isoelectronic and have the same electronegativity. Since the lattice misfits are +5% and ;Several techniques of thermal He atom scattering are used here to study the structural and dynamical evolution of these systems. In the case of Ag/Pd(111), measurements showed that the first monolayer (ML) is smooth, comprised of pure Ag, and chemically inert. Further Ag deposition leads to an increase in the surface roughness up to 2ML coverage. After this point, the growth continues by diffusion of new adatoms to the step edges and incorporation therein. Phonon dispersion measurements along the crystallographic ;For Cu/Pd(111), the first ML is comprised of a well-ordered CuPd alloy, which is completed at Cu coverages between 0.5 and 0.7 ML. This layer is found to have appreciable chemical reactivity. Phonon dispersion measurements along the...