Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 29: Poster session II (Nanostructures, Magnetism, Particles and clusters, Scanning probe techniques, Time-resolved spectroscopy, Structure and dynamics, Semiconductor surfaces and interfaces, Oxides and insulators, Solid-liquid interfaces)

O 29.51: Poster

Mittwoch, 29. März 2006, 14:30–17:30, P2

Lateral and electrical forces during the manipulation of organic molecules — •Lars Zimmerli, Oliver Pfeiffer, Thilo Glatzel, Sabine Maier, Enrico Gnecco, Alexis Baratoff, and Ernst Meyer — Institute of Physics, Klingelbergstr 82, 4056 Basel, Switzerland

The measurement of lateral forces between the tip of a force microscope and atomic scale features on a surface is an important issue in manipulation experiments. Feedback- controlled excitation of the torsional eigenmode of a rectangular cantilever beam forces the tip to oscillate parallel to the surface. We already reported the general capability to measure lateral forces using this technique [1, 2] at a step edge and we now observe these forces during the manipulation of organic molecules.

We have studied the lateral forces while manipulating single Cu-TBPP molecules on Cu[100]. Conservative and dissipative lateral interactions will be discussed while the tip is close or even directly above one porphyrine molecule. These results will be compared with those measured over a step edge or an impurity on the surface. We also studied Kelvin probe force microscopy which yields detailed information of topography and local work function on the nanometer scale. We identified distinct differences in energetics between the Cu-TBPP molecules and the substrate surface.

[1] O. Pfeiffer et al., Phys. Rev. B 65, 161403 (2002) [2] Ch. Loppacher et al., Phys. Rev. 90, 066107 (2003)