Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 51: Surface chemical reactions I

O 51.3: Vortrag

Donnerstag, 26. März 2009, 16:45–17:00, SCH A01

STM investigations of an electron induced switching process in azobenzene-based structures — •Jörg Henzl and Karina Morgenstern — Universtität Hannover, Institut für Festkörperphysik, Abt. Oberflächen, Appelstr. 2, 30167 Hannover

The cis- trans isomerization of azobenzene molecules in gas phase and in solution is a well studied phenomenon. But only in the recent years first studies of azobenzene molecules adsorbed on single crystal surfaces have been emerged. This system is of particular interest not only from a fundamental point of view but also because of its possible applications in nanotechnology as a molecular switch.

Here we present low temperature scanning tunnelling microscopy measurements of 4-anilino-4'-nitroazobenzene on the Au(111)-surface. Upon adsorption at 250 K the molecules form both meandering lines of single molecules which are guided by the Au(111)-herringbone reconstruction, and a chiral star-shaped structures consisting of six molecules each.

A switching process within a single molecule inside the star-shaped structures is induced by placing the tip of the scanning tunnelling microscope above one molecule and applying a bias voltage of 2.5 V. The other molecules of the star-shaped structure remain unaffected during this manipulation. This reversible and bistable switching process will be discussed in greater detail in this talk.