Dynamic Scaling at the Zero-field 2D Superconducting Transition

Abstract

Zero-field current-voltage (I-V) characteristics of a thin ("two-dimensional") $B{i}_{2}S{r}_{2}CaC{u}_2{O}_{8+\delta }$ crystal are reported and analyzed in two ways. The "conventional" approach yields ambiguous results while a dynamical scaling analysis 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. A value of $z\simeq 5.6$ is obtained for the dynamical critical exponent, and is corroborated by data from other 2D superconductors. A simple dynamical model is presented to account for the results.

Minor revisions, 4 pages LaTeX, 3 .eps figs