Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Transport: Fluctuations and Noise

TT 21.3: Vortrag

Dienstag, 24. März 2009, 14:45–15:00, HSZ 304

Control of the conductance and noise of driven carbon-based Fabry-Perot devices — •Luis E. F. Foa Torres and Gianaurelio Cuniberti — Institute for Materials Science and Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden, Germany.

Here we report on the suppression and revival of the Fabry-Perot conductance interference pattern through a carbon-based three terminal device [1]. By using Green functions techniques in the Floquet replica space as our general framework, we show that control of the interference pattern can be achieved by tuning the ac field strength and frequency. For frequencies matching integer multiples of the level spacing of the system a manifestation of the wagon-wheel effect in the quantum domain takes place as the conductance remains irresponsive to the external field. When this condition is not satisfied, tuning the intensity of the ac gating induces an alternation of suppression and partial revival of the conductance interference pattern. In contrast, the phase sensitive current noise behaves as in the static case only when the frequency is commensurate with twice the mean level spacing. This scenario is tested for the case of carbon nanotubes, where the scaling properties of noise with tube radius and length are also explored.

[1] L. E. F. Foa Torres and G. Cuniberti, arxiv: 0807.4953.