Magnetoconductance in single-wall carbon nanotubes: Electron-electron interaction and weak localization contributions

The positive and negative magnetoconductance (MC) data [J. Vavro et al., Phys. Rev. B 71, 155410 (2005)] in various single-wall carbon nanotube samples are analyzed by taking into account the electron-electron interaction (EEI)contribution, in addition to the weak localization (WL) regime. The low field MC data shows an $H^2$ dependence, in accordance with the EEI and WL models. The contribution from EEI to the total MC is further confirmed from the universal scaling of MC relation $[\{\Delta\sigma/T^{1/2}\}$ vs (H/T) plots], showing that EEI plays a significant role at higher fields and lower temperatures. Intrinsic parameters such as inelastic scattering length $l_{in}$ extracted for barely metallic sample (120 S/cm at 300 K)follow the $T^{-3/4}$ dependence due to the inelastic electron-electron scattering in the dirty limit. The $l_{in}$ for highly conducting sample (3570 S/cm at 300 K) follows a $T^{-0.4}$ dependence. The various order parameters helps us to characterize the system in a disorder-tuned metal-insulator transition scenario.