Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 15: Scanning Probe Techniques: STM/AFM
O 15.9: Talk
Monday, March 16, 2015, 17:00–17:15, MA 043
Probing the Polar Nature of Bonds by means of Atomic Force Microscopy — •Florian Albrecht1, Martin Fleischmann2, Manfred Scheer2, Martin Ondráček3, Pavel Jelinek3, and Jascha Repp1 — 1Institute of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany — 2Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany — 3Institute of Physics of Czech Academy of Science, 16253 Prague, Czech Republic
Recently, Kelvin probe force spectroscopy (KPFS) has been shown to be a powerful tool to detect charge distributions with sub molecular resolution [1, 2]. We performed KPFS measurements in a low temperature combined scanning tunneling and atomic force microscope with functionalized tips on different types of molecules - some of them exhibiting polar bonds. Whereas KPFS represents the charge distribution with moderate resolution for large tip-molecule separations, it fails for short distances. We therefore introduce a novel technique, in which the dependence of the electric field on tip-sample distance is exploited to map out charges. Thereby, we were able to resolve the intramolecular charge distribution with unprecedented lateral resolution.
[1] F. Mohn, et al., Nature Nano. 7, 227 (2012)
[2] B. Schuler, et al., Nano Letters 14, 3342 (2014)