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O: Fachverband Oberflächenphysik

O 65: Methods: Theory and Experiment

O 65.8: Vortrag

Donnerstag, 28. Februar 2008, 13:45–14:00, MA 141

The Surface state of Au(111) and characterization of the tunneling tip in STM — •Berndt Koslowski, Anna Tschetschetkin, Stefania C. Bobaru, and Paul Ziemann — Institut für Festkörperphysik, Universität Ulm, D-89069 Ulm, Germany

Based on a recently developed method for recovering the electronic density of states (DOS) from Scanning Tunneling Spectroscopy (STS) data [1], we re-examine the well-known Shockley-like surface state (SS) of Au(111) at 6.2K. To do so, we employ the 3D WKB approximation for the special case of a 2-dimensional SS leading to an analytical solution for the DOS recovery. The goal of this contribution is threefold: firstly, we show why the SS does not show up as a step function in STS. Secondly it will be demonstrated, how the SS can be exploited to extract information about the tip DOS resulting in a *calibrated* tunneling sensor. Thirdly, we discuss details of the tunneling spectra such as the cross-over from 2D to 3D tunneling below the band edge of the SS.

[1] B. Koslowski, Ch. Dietrich, A. Tschetschetkin, P. Ziemann, Phys.Rev. B 75, 035421 (2007).