Berlin 2005 – scientific programme
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O: Oberflächenphysik
O 55: Epitaxie und Oberfl
ächenreaktionen
O 55.9: Talk
Wednesday, March 9, 2005, 12:45–13:00, TU EB107
STM studies on the electronic properties of single Au atoms and Au dimers on a thin Al2O3 film on NiAl(110) — •Maria Kulawik, Niklas Nilius, Hans-Peter Rust, and Hans-Joachim Freund — Fritz-Haber-Institut der MPG, Abteilung Chemische Physik, Faradayweg 4-6, 14195 Berlin
The adsorption and diffusion of metal atoms on oxide surfaces play key roles in heterogeneous catalysis, notably for the regeneration of the catalytically active species. Despite the importance of these processes, only little is known on the atomic level, which is mainly due to the high complexity of real catalysts. Therefore, the study of model systems is essential to gain a fundamental understanding of these processes.
Here, we have investigated the electronic structure of single Au atoms on a thin Al2O3 film on NiAl(110) by Scanning Tunneling Microscopy and Spectroscopy (STM/STS) at 5 K. STS spectra of Au monomers exhibit single resonances between 2 and 3 eV whereby the energy position depends on the adsorption site. For Au dimers, a split of this peak is observed. Conductance images reveal the spacial distribution of the LDOS.