Low-energy deposition of Co onto Co islands on Ag(100): Effect on submonolayer growth

Abstract

Using classical molecular dynamics (MD) methods and rate equations, we have studied the effect of Co deposition onto a Co island at a Ag(100) surface. In the MD simulations, Co atoms were deposited on islands of sizes from $2\ifmmode\times\else\texttimes\fi{}2$ to $6\ifmmode\times\else\texttimes\fi{}6$ atoms with an energy of $25\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ at an incident angle of 20 degrees off normal. From the MD simulation results, we determined the functional form of the fragmentation kernel used in the rate equations as well as its parameters. The MD results also showed that irradiation-induced detachment from the island is common, while dissociation events of the island are very rare. Studying the growth process using rate equations, which included the restrictions deduced from the MD results, gave us island size distributions that agree with experimentally measured distributions. Thus, our results show that the submonolayer growth process can be explained solely by irradiation-induced detachment from the island.