Magnetoconductance experiments at LNCMP in Toulouse were done in ballistic multiwalled carbon nanotubes threaded by magnetic fields as large as 55 T. In the high temperature regime (100 K), giant modulations of the conductance, mediated by the Fermi level location, are unveiled. The experimental data are consistently analyzed in terms of the field-dependent density of states of the external shell that modulates the injection properties at the electrode-nanotube interface, and the resulting linear conductance.
a) Experimental magnetoconductance for selected ?g values and their corresponding theoretical curves at 100 K (black dashed curves). The curves are shifted by 0.2G 0 for clarity. (b) Sketch of the Schottky barrier at the contact with the parameters used in the model. (c) Corresponding Schottky barrier profiles at F 0 /2 for the different backgate voltages. (d) 2D experimental graph of G(?g ;F) (left-hand graph) and the theoretical one (right-hand graph).
This is the first unambiguous experimental evidence of Aharonov-Bohm effect in clean multiwalled carbon nanotubes.
This work was published in :
B. Lassagne, J.P. Cleuziou, S. Nanot, W. Escoffier, R. Avriller, S. Roche, L. Forró, B. Raquet and J.M. Broto Aharonov-Bohm conductance modulation in ballistic Carbon nanotubes Phys. Rev. Lett. 98 , 176802 (2007)