Random-matrix approach to quantum electron transport in metallic carbon nanotubes

The properties of quantum electron transport through metallic carbon nanotubes with several conducting channels are investigated by the random-matrix approach. Starting from the unique scattering symmetry observed in metallic carbon nanotubes with long-range impurity potential, we can derive the random-matrix representation in which the classical and quantum processes are clearly separated. With increasing system length, the system approaches a fixed point, where only one channel is perfectly conducting and other channels are completely closed. It is shown that such behavior should be attributed to the anti localization effect. We can describe the decoherence effect on the total transmission probability <T> within the random-matrix theory. For a nanotube of length L, we obtain <T> similar to L-phi/L for l less than or similar to L-phi much less than L, where l and L-phi are the mean free path and the phase coherence length, respectively.