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RESEARCH PRODUCT

Adatom Island Diffusion on Metal Fcc(100) Surfaces

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We study the energetics and atomic mechanisms of diffusion of adatom islands on fcc(100) metal surfaces. For small islands, we perform detailed microscopic calculations using semi-empirical embedded-atom model and glue potentials in the case of Cu and Al, respectively. Combining systematic saddle-point search methods and molecular statics simulations allows us to find all the relevant transition paths for island motion. In particular, we demonstrate that there are novel many-body mechanisms such as internal row shearing which can, in some cases, control the island dynamics. Next, we show how using the master equation formalism, diffusion coefficients for small islands up to about five atoms, can be calculated analytically from the knowledge of the transition rates. In the case of larger islands, we perform large-scale kinetic Monte Carlo simulations based on microscopic single particle energetics. These results show that, as a function of the island size, there is a crossover from periphery dominated mass transport to a regime controlled by the motion of vacancies inside the island.