Conduction in carbon nanotubes through metastable resonant statesZ. Zhang1, D. A. Dikin2, R. S. Ruoff2 and V. Chandrasekhar1
1 Department of Physics and Astronomy, Northwestern University Evanston, IL 60208, USA
2 Department of Mechanical Engineering, Northwestern University Evanston, IL 60208, USA
received 19 July 2004; accepted in final form 7 October 2004
published online 5 November 2004
We report here on electrical measurements on individual multi-walled carbon nanotubes that show that the presence or movement of impurities or defects in the carbon nanotube can radically change its low-temperature transport characteristics. The low-temperature conductance can either decrease monotonically with decreasing temperature, or show a sudden increase at very low temperatures, sometimes in the same sample at different times. This unusual behavior of the temperature dependence of the conductance is correlated with large variations in the differential conductance as a function of the dc voltage across the wire. The effect is well described as arising from quantum interference of conduction channels corresponding to direct transmission through the nanotube and resonant transmission through a discrete electron state, the so-called Fano resonance.
73.63.Fg - Nanotubes.
85.35.Kt - Nanotube devices.
73.20.Hb - Impurity and defect levels; energy states of adsorbed species.
© EDP Sciences 2004