NONLINEAR CONDUCTIVITY OF BI2SR2CUO6 SINGLE-CRYSTALS

We have observed the nonlinear current-voltage characteristics of Bi2S r2CuO6 single crystals in the weakly localized regime (WLR), in which the conductivity indicates a logarithmic dependence both on temperatur e and on magnetic fields. The conductivity in low voltage remaines con stant (Ohmic behavior). Upon application of a voltage higher than the threshold electric field 0.1V/cm, the conductivity begins to increase. The observed threshold of the electric field is much smaller than the value of 200V/cm estimated from the model which Anderson et al. (1979 ) introduced to explain the nonlinear conductivity shown in the WLR of thin metal films.