Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 5: Dynamics of Molecules on Surfaces

O 5.1: Vortrag

Montag, 7. März 2016, 10:30–10:45, S053

Electric field driven chemical reaction of single molecules by Scanning Tunneling Microscopy — •Tomasz Michnowicz¹, Bogdana Borca¹, Verena Schendel¹, Ivan Pentegov¹, Ulrike Kraft¹, Hagen Klauk¹, Peter Wahl^1,2, Uta Schlickum¹, and Klaus Kern^1,3 — ¹Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany — ²University of St Andrews, School of Physics and Astronomy, KY16 9SS St Andrews, UK — ³Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland

Scanning Tunneling Microscopy allows the manipulation of individual organic molecules by various kinds of stimuli, for example tunneling current, electric field or precise mechanical interaction. Here we present a study of chemical bond formation of individual organic molecules, tetracenothiophene (TCT), to the copper (111) surface by making use of the electric field present between tip and surface. Ramping the bias voltage, while positioning the tip apex precisely above the thiophene group, results in a change of the molecule’s topographic appearance, which we attribute to the breaking of the thiophene group and a chemical bond formation to the copper surface atoms. The threshold voltage, that has to be overcome in order to trigger the reaction, depends linearly on the tip-molecule distance. This is a characteristic behaviour for electric field driven processes. In addition, we measured the single molecule’s conductance of about 0.14 G₀ for molecules before reaction and 0.21 G₀ for molecules after reaction (G₀: quantum of conductance).