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O: Fachverband Oberflächenphysik

O 40: Transport: Molecular Electronics I (TT jointly with O)

O 40.1: Vortrag

Mittwoch, 2. April 2014, 09:30–09:45, HSZ 304

Electrical transport through ferrocene molecules using MCBJ — •Karthiga Kanthasamy, Christoph Tegenkamp, and Herbert Pfnür — Institut für Festkörperphysik (ATMOS), Leibniz Universität Hannover

In order to understand the electrical behavior of molecules we fabricate a stable atomic gold contact by Mechanically Controllable Break Junction(MCBJ). We study the electrical transport through ferrocenedithiol (FDT) molecules because of its rotational flexibility with respect to two cyclopentadienyl(Cp) rings without activation threshold and high conductance.

The molecules are chemisorbed on the Au atomic contact, as confirmed by XPS characterization on Au thin film. After insertion of FDT molecules, measuring conductance versus contact distance at constant voltage 1 mV there are characteristic stepwise changes below 1 G₀ with a very pronounced plateau at 0.4 G₀. In the range 0.1 G₀ < conductance < 0.4 G₀, we measured IV-curves at room temperature and 80 K. Detailed analysis of IV-curves exhibit characteristic peak in the first derivative. The voltage at the maxima can be identified with the excitation of C-H bending, C-H stretching vibrational modes indicating resonantly enhanced conductance by vibrational excitation. The influence of different anchoring groups in the electronic transport will be shown.