Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 47: Metal substrates: Adsorption of organic / bio molecules V
O 47.5: Vortrag
Mittwoch, 24. März 2010, 11:30–11:45, H36
Selective bonding and apparent symmetry of single Cobalt-Phthalocyanine on a Cu(111) surface — •Deung-Jang Choi1, Benjamin W. Heinrich1, Cristian Iacovita1, Thomas Brumme2,3, Laurent Limot1, Mircea V. Rastei1, Jens Kortus2, Werner A. Hofer4, and Jean-Pierre Bucher1 — 1IPCMS(CNRS), UMR 7504, Université de Strasbourg, France — 2Institut für Theoretische Physik, TU Bergakademie Freiberg, Germany — 3Institute for Materials Science and Max Bergmann Center of Biomaterials, Dresden University of Technology, Germany — 4Surface Science Research Centre, University of Liverpool, United Kingdom
Low-temperature scanning tunneling microscopy and spectroscopy are combined with ab initio calculations to study isolated CoPc molecules on a Cu(111) surface. Tip-assisted manipulation and constant-height scans are employed to resolve the adsorption geometry of the molecule and to obtain high-resolution maps of the intramolecular conductance. We show that nitrogen atoms play a central role in the adsorption and the conductance of the molecule on Cu(111). The preferential adsorption of nitrogen on top of surface atoms centers CoPc on a bridge site of the Cu lattice and anchors the molecule to the surface with an adsorption energy estimated at 6.9 eV. Furthermore, we show that the p-orbitals of the nitrogen atoms along with the d-orbitals of cobalt govern the molecular conductance, the former contribution being responsible for the symmetry of CoPc on the surface. The symmetry is seen to change at selected biases due to electronic effects, which are discussed in detail.