Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 90: Electronic structure III

O 90.5: Talk

Thursday, March 17, 2011, 18:15–18:30, WIL C107

Local Electronic Structure and Surface Potential of Atomic Chains on Si(111)5x2-Au — •Ingo Barke, Stefan Polei, Kristian Sell, Viola von Oeynhausen, and Karl-Heinz Meiwes-Broer — Universität Rostock , Institut für Physik, Universitätsplatz 3, D-18051 Rostock

Quasi one-dimensional surface reconstructions are formed by various metals adsorbed on flat or vicinal Si(111). On Si(111)5x2-Au the spatially resolved density of states is measured by scanning tunneling spectroscopy. Spectral features are assigned to particular structural elements based on a recently proposed model [1]. In this contribution two key elements are discussed: (1) the Si honeycomb chain channel (HCC) with locally graphitic structure which is found on many chain systems, and (2) Si adatoms with an average coverage of 0.25 atom per 5x2 unit cell leading to pronounced bright protrusions in STM images. While the latter result in local electron doping, the HCC give rise to a pronounced corrugation of the surface potential perpendicular to the chains. These variations manifest themselves in energy modulations of unoccupied, image-state derived electron states.

[1] S. C. Erwin, I. Barke, and F. J. Himpsel, Phys. Rev. B 80, 155409 (2009).