Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Transport - Poster Session
TT 28.6: Poster
Donnerstag, 29. März 2007, 14:00–17:45, Poster A
Coherent laser control of the current through molecular junctions — Guangqi Li1, Michael Schreiber2, and •Ulrich Kleinekathöfer1 — 1International University Bremen (Jacobs University Bremen as of spring 2007), Campus Ring 1, 28759 Bremen — 2Institut für Physik, Technische Universität Chemnitz, 09107 Chemnitz
The tunneling current through a single site molecular junction coupled to two leads is studied under the effect of an external field using a master equation approach [1]. In the case of a small bias and a high carrier frequency of the external field, the current through the molecular junction vanishes completely for certain parameters of the external field. This phenomenon is known as coherent destruction of tunneling [2]. For larger bias voltages, further tunneling channels participate in the electron conduction and therefore the current does not vanish anymore. This is known as photon-assisted tunneling and leads to steps in the current-voltage characteristics. The described phenomenon could be used for ultrafast optical switching of the current through molecular junctions.
[1] S. Welack, M. Schreiber, and U. Kleinekathöfer, J. Chem.
Phys. 124, 044712 (2006).
[2] U. Kleinekathöfer, G.-Q. Li, S. Welack, and M. Schreiber,
Europhys. Lett. 75, 139 (2006).