Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 40: TR: Nanoelectronics III: Molecular Electronics 2
TT 40.6: Vortrag
Freitag, 26. März 2010, 12:45–13:00, H20
Vibronic Cooling Mechanisms in Molecular Junctions — •Rainer Härtle1, Michael Thoss1, Roie Volkovich2, and Uri Peskin2 — 1Theoretische Festkörperphysik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 7/B2, D-91058 Erlangen, Germany — 2Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
We study vibrational nonequilibrium effects in charge transport through single-molecule junctions. Vibrational degrees of freedom of a molecular junction can be excited by inelastic electron transmission processes (local heating). Such processes are active even if the junction is in its vibrational ground state or thermal equilibrium, and manifest themselves in pronounced structures in the junction's transport characteristics. Cooling processes, however, can usually only occur if the junction is driven out of thermal equilibrium and require the junction to provide vibrational energy. We show that these processes may be as important as heating processes and that local cooling may induce transport phenomena, which are not present in thermal equilibrium. The methodology we have used to study these transport phenomena includes a nonequilibrium Green's function approach [1,2,3], and a master equation approach [3], which provide complementary schemes.
[1] M. Galperin, A. Nitzan, M. A. Ratner, Phys. Rev. B 73, 045314 (2006).
[2] R. Härtle, C. Benesch, M. Thoss, Phys. Rev. B 77, 205314 (2008).
[3] R. Härtle, C. Benesch, M. Thoss, Phys. Rev. Lett. 102, 146801 (2009).