Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 50: Time-resolved spectroscopy II
O 50.1: Vortrag
Freitag, 31. März 2006, 11:15–11:30, WIL C207
Time-resolved two-photon photoemission from the Si(557)Au surface — •Tilman K. Rügheimer1, Franz J. Himpsel2, and Thomas Fauster1 — 1Lehrstuhl für Festkörperphysik, Institut für Physik der Kondensierten Materie, Universität Erlangen, Staudtstr. 7, D-91058 Erlangen — 2Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, USA
Atomic chains of gold on silicon surfaces have attracted interest as model systems for one-dimensional conductors. For the Si(557)Au surface electronic states at the gold chains and the step edges are predicted by density functional theory [1]. Angle resolved photoemission [2] and scanning tunneling spectroscopy [3] assign the conduction to the gold chains and the step edges, respectively.
We have carried out two-photon photoemission experiments to clarify the electronic structure of the Si(557)Au surface. Pinning of the Fermi level and two strongly dispersing initial states below the Fermi energy have been found. A conduction band feature shows a complex population dynamics in time-resolved measurements. Finally, our results are compared to recent ab initio calculations [1].
[1] D. Sanchez-Portal et al., Phys. Rev. Lett. 93 (2004) 146803
[2] J. N. Crain et al., Phys. Rev. B 69 (2004) 125401
[3] H. W. Yeom et al., Phys. Rev. B 72 (2005) 035323