Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 17: Postersitzung II: Transport, Quantenkoh
ärenz, Quantenflüssigkeiten

TT 17.1: Poster

Dienstag, 9. März 2004, 14:30–19:00, Poster A

Charge transport through a two-site system driven by a high-frequency field — •Michael Straß, Jörg Lehmann, Sébastien Camalet, Sigmund Kohler, Gerd-Ludwig Ingold, and Peter Hänggi — Institut für Physik, Universität Augsburg

We study the transport properties of a two-site system driven by an external oscillating field. Possible experimental realizations are molecular wires in laser fields or coupled quantum dots exposed to microwave radiation. The current and the associated noise are computed within a high-frequency approximation in which the time-dependent system is mapped to a static one described by renormalized, effective parameters that depend on the driving frequency and amplitude [1]. This allows for an illustrative explanation of the characteristic dips in the noise characterized by the Fano factor.

We compare our analytic results of the Fano factor with an exact numeric solution obtained by a Floquet approach [2]. The external field allows to switch between three qualitatively different situations: either transport through a tunnel contact, a two-barrier setup or a open channel. Therefore tunning the field permits a control of the transport properties of two-site systems in molecular electronic devices.

[1] S. Kohler, S. Camalet, M. Strass, J. Lehmann, G.-L. Ingold, and P. Hänggi, Chem. Phys. (in press), cond-mat/0306704.

[2] S. Camalet, J. Lehmann, S. Kohler, and P. Hänggi, Phys. Rev. Lett. 90, 210602 (2003).