Diffusion on aluminum-cluster surfaces and the cluster growth
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|Julkaisu||Physical Review B - Condensed Matter and Materials Physics|
|DOI - pysyväislinkit|
|Tila||Julkaistu - 1 tammikuuta 1998|
Diffusion of adatoms have been studied on fcc polyhedral aluminum-cluster surfaces by molecular-dynamics simulations using the effective-medium theory. Diffusion of adatoms has been shown to take place by hopping along (Formula presented) facets at very low temperatures. Diffusion from one (Formula presented) facet to other (Formula presented) facets takes place at higher temperatures through a variety of mechanisms, and finally diffusion to and along (Formula presented) facets takes place at high temperatures. Diffusion from (Formula presented) to (Formula presented) facets is possible only close to the melting temperature of the cluster. The appearance of different diffusion processes as a function of temperature is in good agreement with the calculated activation energies of diffusion mechanisms along different facets and from one facet to another, including different hopping and exchange processes as well as more exotic events like the chain mechanism through a (Formula presented) facet between two (Formula presented) facets. Observed diffusion mechanisms imply that fcc clusters can grow epitaxially, having only (Formula presented) facets in accord with experimental observation. Our dynamical simulations of cluster growth support these findings.