Local and non-local shot noise in multiwalled carbon nanotubes

We have investigated shot noise in multiterminal, disordered multiwalled carbon nanotubes (MWNTs) at 4.2K over the frequency f = 600-850 MHz. Quantitative comparison of our data to semiclassical theory, based on non-equilibrium distribution functions, indicates that a major part of the noise is caused by a non-equilibrium state imposed by the contacts. Our data exhibits non-local shot noise across weakly transmitting contacts while a low-impedance contact eliminates such noise almost fully. Within our model we obtain F(tube) < 0.1 for the intrinsic Fano factor of our MWNTs. This behavior cannot be explained by the presence of ballistic channels. Copyright (C) EPLA, 2009