Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
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 42.25: Poster
Mittwoch, 25. März 2009, 17:45–20:30, P2
Coverage-Dependent Faceting of Au Chains on Si(557) — •I. Barke1, F. Zheng2, S. Bockenhauer2, K. Sell1, V. v. Oeynhausen1, K. H. Meiwes-Broer1, and F. J. Himpsel2 — 1Universität Rostock, Institut für Physik, 18051 Rostock — 2Dept. of Physics, University of Wisconsin Madison, 1150 University Ave, Madison, WI 53706
The structural and electronic phase diagram of Au on Si(557) is established using scanning tunneling microscopy (STM) and angle-resolved photoemission (ARPES). Five phases consisting of altogether seven facets are observed in the sub-monolayer regime. Four of them consist of two coexisting structures. In order of increasing Au coverage the five phases are: Si(111)7×7 + Si(112), Si(557)1×2-Au, Si(111)5×2-Au + Si(335)-Au, Si(111)√3×√3-Au + Si(335)-Au, and Si(111)√3×√3-Au + Si(5 5 11)-Au. The relative surface areas of the five phases and seven facets are determined accurately by depositing a Au wedge ranging from 0 to 0.8 monolayer and performing automatic pattern recognition on large-scale STM images. Angle-resolved photoemission spectra are decomposed into contributions from the five phases. The Fermi wave vectors of various facets are identified. Using Si(557)1×2-Au as reference we find a coverage of 3 Au chains per unit cell for the frequently-studied Si(111)5×2-Au surface (instead of the widely-used value of 2 Au chains). The impact of this finding on structural models is discussed.