Surface self-diffusion of a Pt adatom on cuboctahedral and truncated decahedral clusters, size dependence
Department of Maths and Physics, Hunan Institute of Engineering, 411104, Xiangtan, P.R. China
2 Department of Applied Physics, Hunan University, 410082, Changsha, P.R. China
3 Department of Applied Physics, Hunan Agricultural University, 410028, Changsha, P.R. China
Revised: 4 October 2010
Published online: 22 November 2010
The self-diffusion of single Pt adatom on the surface of cuboctahedral and truncated decahedral clusters with 561–10 179 atoms are studied within the context of the many-body potentials obtained via the embedded atom method. The minimum energy diffusion path and the corresponding energy barrier for adatom diffusion on the cuboctahedral and truncated decahedral clusters surfaces are determined through a combination of the quenched molecular dynamics and the nudged elastic band method. The calculated energy barriers are consistent with the available experimental data. The dependence of energy barrier for adatom diffusion across the step edge on the cluster size is found. For the larger cuboctahedral and truncated decahedral clusters, the simulations show that the movement of the adatom is confined to a central region, and the adatom may escape from the center region only at elevated temperatures. In addition, we also find that the truncated decahedral structure is more favorable over the cuboctahedral structure for smaller clusters. The cluster growth experiments support our results.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010