Adatom/vacancy interactions and interlayer mass transport in small two-dimensional Pt clusters on Pt(1 1 1)
2003 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 539, no 1-3Article in journal (Refereed) Published
We use embedded-atom molecular dynamics simulations to follow the dynamics of adatoms, vacancies, and adatom/vacancy pairs on two-dimensional hexagonal Pt19 clusters on Pt(1 1 1) surfaces at 1000 K. All configurations are found to be quite stable and have essentially the same migration mobilities as compact hexagonal clusters. However, the presence of a single vacancy dramatically decreases the lifetime of an adatom on the cluster by a factor of three. This occurs primarily through an enhancement of the rate of push-out/exchange reactions at the outer cluster edge resulting from vacancy-induced softening of edge atom bonds. Overall, adatoms in the presence of vacancies descend to the terrace via vacancy filling 10% of the time, and through reactions with outer cluster edges the remaining 90%. Direct vacancy filling mechanisms are analogous to, and have similar activation energies with, those at outer cluster edges: adatom hopping over descending steps and push-out/exchange reactions. © 2003 Elsevier B.V. All rights reserved.
Place, publisher, year, edition, pages
2003. Vol. 539, no 1-3
Adatoms, Clusters, Growth, Molecular dynamics, Nucleation, Platinum
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-46531DOI: 10.1016/S0039-6028(03)00831-8OAI: oai:DiVA.org:liu-46531DiVA: diva2:267427