Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 38: Poster Session Transport

TT 38.28: Poster

Wednesday, March 16, 2011, 14:00–18:00, P3

Quantum Interference and Dephasing Due to Vibronic Coupling in a Single-Molecule Junction — •Michael Butzin, Rainer Härtle, and Michael Thoss — Theoretische Festkörperphysik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 7/B2, D-91058 Erlangen, Germany

We study quantum interference and dephasing effects in a biphenyl-acetylene-dithiolate molecular junction. To this end, we analyze the molecular orbitals relevant for charge transport through this junction and show that destructive interference effects suppress coherent transport processes. The coupling of the electronic degrees of freedom to the large number of vibrational modes of the junction strongly influences the respective current-voltage characteristics and induces a dephasing mechanism that counteracts the suppression of the current due to destructive interference. To analyze these phenomena we discuss generic model systems using a nonequilibrium Green’s function approach [1]. Moreover, for a molecular junction that exhibits quantum interference effects, we identify the constructive and destructive parts of the corresponding transmission function [2]. Interestingly, in the presence of electron-electron interactions, such destructive interference effects provide a testbed for the elastic co-tunneling approximation [1], which we study employing the exact method of Gurvitz et al. [3].

[1] R. Härtle et al., Phys. Rev. Lett. 102, 146801 (2009).

[2] G. C. Solomon et al., Nano Lett. 6, 2431 (2006).

[3] S. A. Gurvitz, Phys. Rev. B 57, 6602 (1998).