Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 29: Poster session II (Nanostructures, Magnetism, Particles and clusters, Scanning probe techniques, Time-resolved spectroscopy, Structure and dynamics, Semiconductor surfaces and interfaces, Oxides and insulators, Solid-liquid interfaces)
O 29.3: Poster
Mittwoch, 29. März 2006, 14:30–17:30, P2
Electronic properties of the Si(557)-Au surface investigated by STM and STS — •M. Sauter1, R. Hoffmann1, C. Sürgers1, and H. v. Löhneysen1,2 — 1Physikalisches Institut and DFG Center for Functional Nanostructures (CFN), Universität Karlsruhe, D-76128 Karlsruhe — 2Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe
The Si(557)-Au surface is investigated by scanning tunneling microscopy (STM) and spectroscopy (STS) at different temperatures. Previous photoemission data were interpreted in terms of a one-dimensional metallic band at room temperature [1]. However, at T = 260 K the photoemission intensity near the Fermi energy vanishes. This has been attributed either to a Peierls transition [1] or to a shift of the Fermi energy [2]. At room temperature our STM images confirm the chainlike structure due to adatoms adjacent to a diffuse row attributed to the step edge. At T = 77 K images of unoccupied electronic states show a splitting of the step-edge structure but no doubling of periodicity in contradiction with the interpretation of a Peierls transition. In addition, we present high-resolution images that reveal a substructure at the location of the Au-Si bonds. Current-distance measurements have been performed in order to investigate the k-dependence of the tunneling spectra.
[1] J. R. Ahn et al., Phys. Rev. Lett. 91, 196403 (2003).
[2] D. Sánchez-Portal et al., Phys. Rev. Lett. 93, 146803 (2004).