Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 23: Transport: Nanoelectronics III - Molecular Electronics

TT 23.7: Vortrag

Mittwoch, 25. März 2009, 11:15–11:30, HSZ 105

Vibrational Nonequilibrium Effects in Single-Molecule Conductance — •Rainer Härtle and Michael Thoss — Theoretische Chemie, Lichtenbergstrasse 4, D-85747 Garching, Germany

Vibrational nonequilibrium effects in charge transport through single-molecule junctions are theoretically investigated by employing a master equation and a nonequilibrium Green's function approach. For molecules that are asymmetrically bound to the leads, vibrationally coupled charge transport, in particular through a single non-degenerate electronic level, exhibits pronounced rectification and negative differential resistance, which can be solely attributed to vibrational nonequilibrium and electron-hole pair creation processes. Focusing on molecular bridges with multiple electronic states, it is shown that electronic-vibrational coupling triggers a variety of vibronic emission and absorption processes, which influence the conductance properties and mechanical stability of single-molecule junctions profoundly. These processes are analyzed in detail for generic model systems of molecular junctions and for more realistic models that are based on ab-initio quantum chemistry calculations.