Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 78: Surface Dynamics I

O 78.8: Vortrag

Donnerstag, 14. März 2013, 17:45–18:00, H42

Spatial dependence of vibronic excitations — •Niko Pavliček¹, Ingmar Swart², Judith Niedenführ³, Gerhard Meyer⁴, and Jascha Repp¹ — ¹Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany — ²Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, the Netherlands — ³Physikalisches Institut, Westfälische Wilhelms-Universität, Münster, Germany — ⁴IBM Research–Zurich, 8803 Rüschlikon, Switzerland

In organic and molecular electronics the electrons are much more spatially confined as compared to inorganic semiconductors, leading to a much stronger electron-vibron (e-ν) coupling. e-ν coupling therefore gives rise to substantial dissipation in such systems. When an electron tunnels into a given molecule (electron attachment), the nuclei will relax giving rise to the so-called reorganization energy, a process that is usually treated in the Franck-Condon picture.

Here, we show that even for an effective single-level system, the spatial position of the electron injection as well as the wave function strongly affect the e-ν coupling strength. These findings can be rationalized by symmetry arguments, thereby shedding new light onto e-ν coupling in organic and molecular electronics.

To this end, we performed low temperature scanning tunneling spectroscopy experiments on individual pentacene molecules adsorbed on ultrathin insulating films.