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O: Fachverband Oberflächenphysik

O 78: Surface chemical reactions

O 78.2: Vortrag

Donnerstag, 17. März 2011, 15:15–15:30, WIL B122

Reversible bond formation in an atom-molecule complex as a molecular switch — •Fabian Mohn¹, Jascha Repp^2,1, Leo Gross¹, Gerhard Meyer¹, Matthew S. Dyer³, and Mats Persson^3,4 — ¹IBM Research – Zurich, 8803 Rüschlikon, Switzerland — ²Institute of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany — ³Surface Science Research Centre, Department of Chemistry, University of Liverpool, Liverpool, L69 3BX, UK — ⁴Department of Applied Physics, Chalmers University of Technology, SE-412 96, Göteborg, Sweden

We report on the formation of a metal-molecule complex that can be used as a molecular switch. Using a cryogenic scanning tunneling microscope, a covalent bond was formed reversibly between a gold atom and a perylene-3,4,9,10-tetracarboxylic dianhydride molecule supported by a thin insulating film. Atomic force microscopy molecular imaging [Gross et al., Science 325, 1110 (2009)] was employed to determine precisely the atomic structure of the complex, and the experimental results were corroborated by density functional theory calculations. The switching between the bonded and the nonbonded state of the complex was found to be accompanied by a considerable change in the tunneling current and could be reliably controlled by locally applying voltage pulses of according polarity. A new mechanism of bond formation, which involves different charge states of the metal-molecule complex, was identified as the reason for the enhanced reliability compared to bond activation by inelastic electron tunneling.