Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 27: Organic/bio Molecules on Metal Surfaces III
O 27.2: Talk
Tuesday, April 1, 2014, 10:45–11:00, TRE Phy
A single Au adatom on PTCDA:Au(111) – results from ab-inito calculations — •Thorsten Deilmann1, Peter Krüger1, Michael Rohlfing1, Taner Esat2, Christian Wagner2, Ruslan Temirov2, and Stefan Tautz2 — 1Institut für Festkörpertheorie, Universität Münster, D-48149 Münster, Germany — 2Peter Grünberg Institute (PGI-3), Forschungszentrum Jülich, Germany
The electronic properties of organic adsorbates on a noble-metal surface depend on structural and environmental details [1].
Here we investigate the influence of an additional Au adatom on a PTCDA monolayer that is adsorbed on a Au(111) surface. Adsorption structures, electronic spectra and scanning tunneling microscopy (STM) images are calculated within density-functional theory.
The weak binding of PTCDA on Au(111) leads to a large bond distance of more than 3 Å between the molecule and the substrate. We investigate different conceivable adsorption sites for the Au adatom above PTCDA. The most favorable adatom position is about 2 Å above the PTCDA molecule. Alternatively, an Au adatom can be located in the region between the molecules. The electronic structure around EF shows distinct differences for the two absorption sites. If the adatom is above a PTCDA molecule a dominant maximum above the Au adatom is visible in the calculated STM image.
[1] A. Greuling et al., Physica Status Solidi B 250, 2386 (2013).