Dynamic scaling for 2D superconductors in zero magnetic field

Zero-field current-voltage (I-V) characteristics of a thin ('two-dimensional') Bi2Sr2CaCu2O8+delta crystal are reported and analyzed in two ways. The 'conventional' approach yields ambiguous results while the dynamical scaling analysis of Fisher and Huse offers new insights into the Kosterlitz-Thouless-Berezinskii transition. The scaling theory predicts that the universal jump of the I-V exponent alpha should be between z + 1 and 1. We obtain a value of z similar or equal to 5.6 for the dynamical critical exponent, which is corroborated by data from other two-dimensional superconductors. A simple dynamical model is presented to account for the results. (C) 1999 Elsevier Science B.V. All rights reserved.