Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 14: Transport: Nanoelectronics III - Molecular Electronics
TT 14.9: Vortrag
Dienstag, 26. Februar 2008, 11:45–12:00, H 3010
Temperature dependence of the conductance in biphenyl-dithiol single-molecule junctions — •Fabian Pauly1, Janne Viljas1,2, Juan Carlos Cuevas3, and Gerd Schön1,2 — 1Institut für Theoretische Festkörperphysik and DFG-Center for Functional Nanostructures, Universität Karlsruhe, 76128 Karlsruhe, Germany — 2Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany — 3Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
Using a density-functional-based transport method, we study the conduction properties of several biphenyl-derived dithiol (BPDDT) molecules wired to gold electrodes [1]. The BPDDT molecules differ in their side groups, which control the degree of conjugation of the π-electron system. We have analyzed the dependence of the low-bias zero-temperature conductance on the tilt angle ϕ between the two phenyl ring units, and find that it follows closely a cos2(ϕ) law as observed in a recent experiment [2].
In addition, we study the temperature dependence of both the conductance and its fluctuations and find qualitative differences between the examined molecules. We illustrate that the fluctuations of the conductance due to temperature-induced changes in the geometric structure of the molecule can be reduced by an appropriate design.
[1] F. Pauly, J. K. Viljas, J. C. Cuevas, G. Schön, arXiv:0705.3285.
[2] Venkataraman et al., Nature 442, 904 (2006).