Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 56: Metal substrates: Epitaxy, growth and adsorbates
O 56.7: Vortrag
Donnerstag, 26. März 2009, 16:30–16:45, SCH A316
Atom distribution and interactions in AgxPt1−x and AuxPt1−x surface alloys on Pt(111) — •Ralf T. Rötter, Andreas Bergbreiter, Harry E. Hoster, and R. Jürgen Behm — Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm
The atom distributions in AgxPt1−x/Pt(111) and AuxPt1−x/Pt(111) surface alloys were studied by high resolution UHV-STM. These surfaces were prepared by submonolayer Ag (Au) metal deposition on Pt(111), followed by annealing at 900 K or 1000 K, respectively, which in both cases results in surface confined 2D alloys, with equilibrated distribution of the components. Both systems show a tendency towards two-dimensional clustering, which fits well to their known bulk immiscibility. Effective cluster interactions (ECIs) will be derived by a quantitative evaluation of the 2D atom distributions in the surface alloys [1]. By comparing the ECIs for PtAg and PtAu on Pt(111), and considering that Ag and Au have almost similar lattice constants, the results allow conclusion on the physical origin of the tendency for clustering.
[1] A. Bergbreiter et al., Phys.Chem.Chem.Phys. 9 (2007) 5127.