October 30 2007
Carbon nanotubes are model systems which can be used to explore various regimes of transport in low dimensions. We have studied the current fluctuations of two terminal devices based on carbon nanotubes. When they are well coupled to metallic electrodes, carbon nanotubes exhibit an electronic Fabry-Perot interferometer behaviour. One can control the transport with the help of a gate electrode capacitively connected to the circuit. We have found that measuring the noise of the current flowing through these controllable quantum scatterers allows to determine directly the two eigenchannels of the nanotube. The existence of these two channels which are degenerate in simple cases stems from the band structure of grapheme (the so-called K-K’ degeneracy). When the transmission through the nanotube device reaches 1, the noise is strongly suppressed. This yields another example of a noiseless fermionic source, after quantum point contacts.
Shot noise in carbon nanotube based Fabry-Perot interferometers
L.G. Herrmann, T. Delattre et al.
Phys. Rev. Lett. 99, 156804 (2007)