Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 99: Electron and spin dynamics II
O 99.7: Vortrag
Freitag, 18. März 2011, 12:45–13:00, WIL B321
Electron dynamics of atomic gold chains on vicinal Si(111) surfaces — •Kerstin Biedermann and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen, Germany
Atomic wires of noble metals such as gold serve as a model system for the investigation of one-dimensional electron systems. Recent experiments on Si(557)-Au have provided initial information on the unoccupied part of the electronic band structure [1,2]. We extended our research to Si(111)-(5×2)-Au and Si(553)-Au and investigated the electron dynamics of these systems.
Time-resolved two-photon photoemission experiments were carried out using infrared (IR, EIR=1.55 eV) and ultraviolet (UV, EUV=4.65 eV) femtosecond laser pulses. In normal emission the beams were incident on the sample at a glancing angle of 10∘ and their electric field vectors could be aligned either perpendicular to (s-pol.) or parallel (p-pol.) to the plane of incidence in order to evaluate the parity of the electronic states.
For all three surfaces we find an even, short-lived (τ<10 fs) state at about E=EVac−0.6 eV below the vacuum level, which we assign to the n=1 image-potential resonance, and a long lived feature (τ>600 fs) within the bulk band gap of silicon. We present here an analysis of our time- and energy-resolved measurements and discuss the similarities and differences between the surfaces investigated.
[1] J. A. Lipton-Duffin et al., Phys. Rev. B 73, 245418 (2006)
[2] T. K. Rügheimer et al., Phys. Rev. B 75, 121401(R) (2007)