| AVS 54th International Symposium | |
| Surface Science | Tuesday Sessions |
| Session SS2-TuM |
| Session: | Surface Structure and Growth on Metals |
| Presenter: | B. Unal, Ames Lab., Iowa State Univ. |
| Authors: | B. Unal, Ames Lab., Iowa State Univ. V. Fournee, CNRS-UMR7584, France K.J. Schnitzenbaumer, Iowa State Univ. C. Ghosh, Iowa State Univ. C.J. Jenks, Ames Lab., Iowa State Univ. A.R. Ross, Iowa State Univ. T.A. Lograsso, Ames Lab., Iowa State Univ. J.W. Evans, Iowa State Univ. P.A. Thiel, Ames Lab., Iowa State Univ. |
| Correspondent: | Click to Email |
Quasicrystals are non-periodic but well-ordered solids. Their unusual atomic structures foster peculiar surface properties such as low friction and enhanced oxidation resistance. Using scanning tunneling microscope (STM) we have investigated clean surfaces of icosahedral (i) Al-Pd-Mn quasicrystals. By analyzing bulk structural models of i-Al-Pd-Mn quasicrystals, we suggest a relationship between the terminating layers and the clusters that form the basic building blocks of quasicrystals. Using STM, we have also investigated the nucleation and growth of Ag islands on the fivefold surface of an i-Al-Pd-Mn quasicrystal. The temperature dependence of island density suggests that trap sites control nucleation of Ag islands. We identify these trap sites as the cut clusters in the aforementioned structure analysis. Furthermore, we have developed a mean field rate equation model to explain this behavior. Our model suggests that the binding energy between Ag atoms at traps are significantly higher than that of Ag at regular terrace sites and the size of critical clusters is larger than one. This model will allow (qualitative) manipulation of experimental parameters to tailor island characteristic on quasicrystal surfaces.