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O: Fachverband Oberflächenphysik
O 63: Posters: Scanning Probe Methods
O 63.9: Poster
Mittwoch, 2. April 2014, 17:30–21:00, P2
Application of Bardeen’s tunneling formula for the calculation of STM data — •Steffen Seiler1, Roman Kováčik2, and Bernd Meyer1 — 1Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg — 2Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich
The tunneling current in scanning tunneling microscopy (STM) is determined
by a convolution of the electronic structure of the tip and the substrate.
However, in the most commonly used method for calculating STM data, the
Tersoff-Hamann approximation [1], all specific details of the tip electronic
structure are neglected.
One step beyond this simplification is Bardeen’s perturbation approach [2],
in which the tip electronic structure is explicitly taken into account.
Both methods have been implemented in our STM simulation program [3]. The
code was recently largely extended and modified, most importantly by including
multiple k-points and fractional occupation numbers for a proper treatment of
metallic systems.
The program was tested for various oxidized Cu surface structures and tip
models. Different benchmark tests were carried out, all confirming the correct
functionality of the program and giving some interesting insights into the
electronic structure of CuOx monolayers on a Cu(111) substrate.
[1] J. Tersoff, D. Hamann, Phys. Rev. B 31, 805 (1985).
[2] J. Bardeen, Phys. Rev. Lett. 6, 57 (1961).
[3] R. Kováčik, B. Meyer, D. Marx, Angew. Chem. IE,
46, 4894 (2007).