Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 85: Electron and spin dynamics I
O 85.4: Talk
Thursday, March 17, 2011, 17:15–17:30, WIL A317
Unoccupied dimer-bond state at Si(100) surfaces — •Thomas Fauster1, Shin’ichiro Tanaka2, Katsumi Tanumira2, Christian Eickhoff3, Martin Teichmann3, and Martin Weinelt3 — 1Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen, Germany — 2The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan — 3Max-Born-Institut, Max-Born-Str. 2A, D-12489 Berlin, Germany
Two-photon photoemission from Si(100) shows a pronounced resonance for the occupied dangling-bond state Dup at photon energies around 2.95 eV. The polarization dependence indicates an intermediate state with a wave function oriented along the dimer axis. We assign this state to the antibonding dimer-bond orbital forming a surface resonance.
The interaction of the dimer-bond state with the bulk continuum leads to a Fano-like lineshape of the resonance curve. A two-dimensional Fano model including the interaction of the Dup state with bulk states can describe the data very well. The lifetime of the dimer-bond state is below 5 fs. The parameters for the Dup state are known from the description of the resonance curve observed for image-potential resonances.