Island shapes, island densities, and stacking-fault formation onIr(111): Kinetic Monte Carlo simulations and experiments

Abstract

Submonolayer homoepitaxy on $\mathrm{Ir}(111)$ is studied by a refined kinetic lattice Monte Carlo (KLMC) model and compared to results obtained from scanning tunneling microscopy experiments. The KLMC model not only considers individual atomic jumps on regular and stacking-fault sites, but also describes the cooperative motion of small adatom clusters, which determines the temperature-dependent probability of stacking-fault island formation. A complete catalog of diffusion processes at island edges is included that allows one to model the variations of island shapes with temperature. By taking input parameters for cluster and edge diffusion from experiments, calculated island densities as well as the probability of stacking-fault formation agree very well with experimental results for different temperatures. The comparison of simulated and experimental island shapes, however, reveals obvious differences. After systematic modifications of the event database for edge diffusion processes, all features of island shape evolution are well reproduced.