Magnetoresistance of carbon nanotube bundles

Summary form only given. Since the discovery of carbon nanotubes a large number of theoretical studies predicted that their band gap changes significantly between zero and nonzero values depending on the diameter and degree of helicity of the nanotube. A magnetic field is expected either to reduce the band gap or to produce Aharonov-Bohm oscillations, when the tube axis is perpendicular or parallel to the magnetic field respectively. It was previously shown (1) that it was possible to realise a direct measurement of the electrical resistance of a single nanotube bundle. In the present work, we present more detailed results on the electrical resistance of single nanotube bundles. The results of an extensive study on the effect of magnetic field intensity and orientation with respect to sample axis as a function of temperature is reported. The electrical resistance measurements were performed from room temperature down to 10 mK in a magnetic field up to 14T.