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Finite size effects, super-and sub-poissonian noise in a nanotube connected to leads

Marine Guigou·Alexandre Popoff·Thierry Martin·Adeline Crépieux
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Abstract

The injection of electrons in the bulk of carbon nanotube which is connected to ideal Fermi liquid leads is considered. While the presence of the leads gives a cancellation of the noise cross-correlations, the auto-correlation noise has a Fano factor which deviates strongly from the Schottky behavior at voltages where finite size effects are expected. Indeed, as the voltage is increased from zero, the noise is first super-poissonian, then sub-poissonian, and eventually it reaches the Schottky limit. These finite size effects are also tested using a diagnosis of photo-assisted transport, where a small AC modulation is superposed to the DC bias voltage between the injection tip and the nanotube. When finite size effects are at play, we obtain a stepwise behavior for the noise derivative, as expected for normal metal systems, whereas in the absence of finite size effects, due to the presence of Coulomb interactions, a smoothed staircase is observed. The present work shows that it is possible to explore finite size effects in nanotube transport via a zero frequency noise measurement.

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Marine Guigou, Alexandre Popoff, Thierry Martin, Adeline Crépieux. 2007-03-02. Finite size effects, super-and sub-poissonian noise in a nanotube connected to leads. https://doi.org/10.1103/physrevb.76.045104

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