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O: Fachverband Oberflächenphysik

O 6: Metal substrates: Adsorption of organic / bio molecules I

O 6.5: Vortrag

Montag, 22. März 2010, 12:15–12:30, H36

Charging and decharging single molecules — Dagmar Kreikemeyer-Lorenzo, Isabel Fernandez-Torrente, Anna Strozecka, •Katharina J. Franke, and Jose I. Pascual — Fachbereich Physik, Freie Universität Berlin, Germany

The charge state of molecules on surfaces crucially influences their reactivity, electronic transport properties and magnetic state. The mixture of the charge transfer compounds tetramethyl-tetrathiafulvalene (TMTTF) and tetracyanoquinodimethane (TCNQ) on a Au(111) surface leads to a self-assembled monolayer of homomolecular rows. In these structures, the majority of TCNQ becomes charged by accepting a single electron in its lowest unoccupied molecular orbital as evidenced by a Kondo resonance in STM transport experiments. Using the STM tip we can manipulate the charge state and thus its magnetic properties. The charging/decharging depends strongly on the position of the tip above the molecular structures and the applied bias voltage.