Beyond the linearity of current-voltage characteristics in multiwalled carbon nanotubes

We present local and non-local electron transport measurements on individual multi-wall nanotubes for bias voltages between 0 and about 4 V. Local current-voltage characteristics are quite linear. In contrast, non-local measurements are highly nonlinear; the differential non-local conductance can even become negative in the high-bias regime. We discuss the relationship between these results and transport parameters such as the elastic length, the number of current carrying shells and the number of conducting modes.