Weak localization and dimensional crossover in carbon nanotube systems

We investigate the effects of magnetic and electric fields on electron wavefunction interactions in single walled carbon nanotube bundles. The magnetoresistance measurements performed at 4.2 K and the dependence of the data upon the electric field reveal good agreement with weak localization theory. An electrical field conditioned characteristic length is associated to ohmic-non ohmic transition, observed below 85 K, in current voltage characteristics. This length results equal to the average bundles diameter just at T ≅ 85 K, indicating that 2D–3D crossover is responsible for the observed conductance transition.