Abstract Submitted to the    NANOTUBE'04 Conference:

Theoretical studies on electronic transport properties of carbon nanotube (CN) demonstrate that small diameter CN behave like unconventional mesoscopic system [1,2]. For instance, in the quasi-ballistic regime, weak localization (WL) due to backscattering along the circumference of the tube, flux-dependent density of states (DOS) oscillations and Fermi level location interplay the magneto-transport in a very unusual manner [1].
Here, we present transport and magneto-transport experiments on double wall carbone nanotubes (DWNT), using the 62T pulsed magnetic field LNCMP facilities. Resistivity versus temperature and differential conductivity experiments give evidences for electronic transport through an interacting disorder metal. Our high magnetic field measurements are mainly focused on the high kinetic energy regime, eV>kT, involving massive and massless subbands. In the high temperature regime, large positive magneto-conductance which reaches saturation around 60T gives evidence for quasi-2D WL in DWNT. At low temperature, both geometrical field configuration and gate voltages drastically change the magnitude and the sign of magneto-resistance. This unconventional magneto-resistance behavior is ascribed to the magnetic field effect on the CN band structure, which is probed by tuning the location of the Fermi level. We bring experimental evidence of van Hove singularities displacement under the high magnetic field regime and its interplay with the magneto-transport.

References :

[1] S. Roche & al., Phys. Rev. B 64 (2001) 121401(R); S. Roche and R. Saito, Phys. Rev. Lett. 87 (2001) 246803. F. Triozon et al., Phys. Rev. B Rapid Comm. (in press).
[2] T. Seri & al., J. Phys. Soc. Jpn 66, 169 (1997); T. Ando, Semicond. Sci. Technol. 15, (2000) R13.