Island-size selectivity during 2D Ag island coarsening on Ag(111).

We report on the early stages of submonolayer Ag island coarsening on the Ag(111) surface carried out using kinetic Monte Carlo simulations for several temperatures. Our simulations were performed using a very large database of processes identified by their local environment and whose activation barriers were calculated using the semi-empirical interaction potentials based on the embedded-atom method. We find that during the early stages, coarsening proceeds as a sequence of selected island sizes, creating peaks and valleys in the island-size distribution. This island-size selectivity is independent of initial conditions and results from the formation of kinetically stable islands for certain sizes as dictated by the relative energetics of edge atom detachment/attachment processes together with the large activation barrier for kink detachment. Our results indicate that by tuning the growth temperature it is possible to enhance the island-size selectivity.