Dilute Cu nanostructure stabilized by substrate-mediated interactions on Cu(111): Kinetic Monte Carlo simulations

摘要

The homoepitaxial growth of Cu on Cu(111) is studied by kinetic Monte Carlo simulations at temperature 15 K and at coverage ranging from 0.005 to 0.04 monolayer (ML). It is shown that substrate-mediated interactions between adatoms lead to the formation of dilute nanostructures with an average nearest-neighbor distance a few times longer than an equilibrium adatom-adatom distance. Morphology of the nanostructure depends on coverage and annealing time. At coverage lower than 0.02 ML short linear chains develop. During annealing the chains evolve into small dilute clusters. At coverage in the range of 0.02-0.04 ML the Cu adatoms need 10-20 min to self-organize into dilute islands with local hexagonal structure. The simulation reveals the existence of energetically favorable adsorption sites at the step edge on the Cu(111) surface that stimulate aggregation of adatoms near the step.