Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: STM/AFM: New Approaches
O 15.7: Vortrag
Montag, 7. März 2016, 16:45–17:00, H24
Intramolecular force contrast and dynamic current-distance measurements at room temperature — •Sonia Matencio1,2, Ferdinand Huber1, Alfred J. Weymouth1, Carmen Ocal2, Esther Barrena2, and Franz J. Giessibl1 — 1Department of Physics, University of Regensburg, Germany — 2Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Spain
AFM can be used to probe the internal atomic structure of molecules [1]. Intramolecular resolution requires an unreactive tip and has been achieved at low temperatures. In the presented work we demonstrate intramolecular and intermolecular force contrast at room temperature on PTCDA molecules adsorbed on a Ag/Si(111)−√3×√3 surface [2].
In addition, the oscillating force sensor allows us to dynamically measure the vertical decay constant of the tunneling current, κ [3]. The precision of the κ measurement was increased by quantifying the transimpedance of the current to voltage converter and accounting for the tip oscillation. The obtained κ maps show contrast between the two non equivalent PTCDA molecules of the herringbone phase giving evidence of a different tunneling barrier height.
[1] L. Gross et al. Science 325, 1110 (2009).
[2] F. Huber, S. Matencio et al. Phys. Rev. Lett. 115, 066101 (2015).
[3] M. Herz et al. Appl. Phys. Lett. 86, 153101 (2005); G. Binnig et al. Surf. Sci. 126, 236 (1983).