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 42.32: Poster

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

Field Emission Resonances on Junctions between Si(111)7x7 and Si(111)5x2-Au — •Stefan Polei, Ingo Barke, Kristian Sell, Viola v. Oeynhausen, and Karl-Heinz Meiwes-Broer — Institut für Physik, Universität Rostock, Universitätsplatz 3, D-18051 Rostock

The image state derived field emission resonances (FER) are investigated on a Si(111)7x7 substrat which is partially covered by the quasi one-dimensional Si(111)5x2-Au structure. These states can be observed by dI/dV measurements of the unoccupied energy range if the STM is operated in a field emission mode. A shift of the FER peak positions on Si(111)7x7 patches vs. Si(111)5x2-Au patches is found which happens on a scale of one nanometer. The origin of that shift is attributed to work function differences [1] caused by the different Fermi level pinning. The results are discussed in view of local work function changes determined by I(Z) spectroscopy across a (7x7)-(5x2-Au) junction.

[1] H. C. Ploigt, C. Brun, M. Pivetta, F. Patthey, and W. D. Schneider, Phys. Rev. B 76, 195404 (2007).