Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 37: Transport - Fluctuations and Noise

TT 37.6: Vortrag

Mittwoch, 9. März 2005, 11:30–11:45, TU H3027

Shot noise in AC-driven nanoscale conductors — •Sigmund Kohler, Michael Strass, Jörg Lehmann, Sébastien Camalet und Peter Hänggi — Institut für Physik, Universität Augsburg, 86135 Augsburg

An ac drving force can significantly modify the electron transport through nanoscale conductors. Some paradigmatic effects in such systems are the current enhancement by resonant driving, the induction of a ratchet or pump current, and the suppression of the DC current by the purely coherent influence of the driving field [1,2]—their experimental observability depends crucially on whether the current flows at a tolerant noise level. For the investigation of the current noise in the mentioned situations, we employ a Floquet theory for periodically time-dependent coherent conductors which provides both the current and its noise properties. If the driving frequency is either large or close to a resonance, the time-dependent transport setup can be approximated by a static effective system which consists of a renormalized conductor Hamiltonian and an effective distribution function for the lead electrons. The analytical results are tested against an exact numerical solution.

[1] S. Camalet, S. Kohler, P. Hänggi, Phys. Rev. B 70, 155326 (2004)

[2] S. Kohler, J. Lehmann, and P. Hänggi, submitted to Phys. Rep.; cond-mat/0409251.