Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)

O 42.77: Poster

Mittwoch, 25. März 2009, 17:45–20:30, P2

Vibrational spectroscopy of the rough Cu(111) surface — •Diana Vogel, Olaf Skibbe, and Annemarie Pucci — Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, D-69120 Heidelberg

It is known that defect sites on a surface have a strong influence on adsorbates due to the changed electronic structure compared to the clean surface. In this work we characterize the rough Cu(111) surface by using High-Resolution Electron Energy Loss Spectroscopy (HREELS). The roughness has been produced by evaporating small amounts of copper onto the cooled surface so small islands are assumed to be grown. In our spectroscopic study, a vibrational state has been found at a quite high loss energy compared to the bulk phonon band. After annealing of the surface another vibrational state at an even higher energy has been detected. In analogy to known investigations on stepped copper surfaces the observed vibrational modes can be attributed to low coordinated step atoms of the islands [1]. The observed change of the vibrational spectra with increasing annealing temperature can be related to a morphology change of the islands. Measurements of the work function change of the surface after evaporating and annealing confirmed this result.

[1] A. Kara, P. Staikov and T. S. Rahman, Phys. Rev. B 61, 5714 (2000).