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HL: Fachverband Halbleiterphysik

HL 49: Molecular electronics (TT, jointly with CPP, HL, MA)

HL 49.10: Talk

Wednesday, March 13, 2013, 12:00–12:15, H2

First principles study of charge and heat transport through π-stacked molecules — •Thomas Hellmuth¹, Marius Bürkle², Fabian Pauly³, and Gerd Schön¹ — ¹Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany — ²Nanosystem Research Istitute, National Institute of Advanced Industrial Science and Technology, Japan — ³Theorie der Nanostrukturen, Universität Konstanz, 78457 Konstanz, Germany

We analyze charge and heat transport properties of π-stacked, multilayered paracyclophane molecules using density functional theory combined with non-equilibrium Green’s function techniques. The conductance of that class of molecules was measured in Ref. 1. Beside the elastic conductance we investigate the not yet measured thermopower and inelastic electron tunneling spectra (IETS). The transmission eigenchannels show that the current is mainly carried by the π system of the paracyclophane molecules and by taking into account different contact geometries, we find that this is independent of the binding motif. While the conductance decays exponentially with increasing molecular length, the thermopower increases linearly and may change its sign. Similarly, we analyze how the IETS and the heat transport depend on the molecular length and vibrational modes in the specific junction geometries.
[1] S. T. Schneebeli et al. J. Am. Chem. Soc. 133, 2136 (2011)