Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)
O 15.20: Poster
Freitag, 4. März 2005, 17:00–20:00, Poster TU D
Structure of a thin oxide film on Rh(100) — •Wilhelm Hofer1, Christof Klein1, Michael Schmid1, Peter Varga1, Lukas Köhler2, Georg Kresse2, Johan Gustafson3, Anders Mikkelsen3, Mikael Borg3, Jesper Andersen3, and Edvin Lundgren3 — 1Allgemeine Physik, TU Wien — 2Materialphysik, Uni Wien — 3Synchrotron Radiation Research, Lund (Sweden)
We have studied the surface oxide of Rh(100) with different experimental and theoretical methods: STM (scanning tunneling microscopy), LEED (low energy electron diffraction), HRCLS (high resolution core level spectroscopy) and DFT (density functional theory). The HRCLS measurements indicated a trilayer RhO2 structure with two oxygen layers and one Rh layer in-between. STM and quantitative LEED revealed a close-to-hexagonal surface with a c(8×2) periodicity. In order to coincide with the square Rh(100) substrate, the hexagonal oxide overlayer is slightly distorted, resulting in a c(8×2) structure. The structural details were obtained by quantitative LEED (Pendry R-factor = 0.16) and DFT calculations. It was found that every seventh of the lower O atoms of the trilayer surface oxide resides in on top positions of the Rh(100) substrate. Ab initio DFT calculations give almost perfect agreement with the LEED results in all atomic coordinates. We therefore regard the trilayer surface oxide model as confirmed and thus the oxygen induced c(8×2) structure as solved. [J. Gustafson et al., submitted to Phys.Rev.B]