Vortex-unbinding and finite-size effects in Tl2Ba2CaCu2O8 thin films

TL;DR

This study investigates the vortex-unbinding mechanism and finite-size effects in Tl2Ba2CaCu2O8 thin films through detailed analysis of current-voltage characteristics, revealing critical behavior consistent with Kosterlitz-Thouless-Berezinskii theory and finite-size influences.

Contribution

It applies multiple scaling approaches to analyze vortex dynamics in high-temperature superconductor thin films, highlighting finite-size effects on phase transition features.

Findings

Vortex-unbinding mechanism with dynamic critical exponent z=2 identified.

Finite-size effects observed, affecting phase transition signatures.

$I$-$V$ relation consistent with KTB theory in Tl$_2$Ba$_2$CaCu$_2$O$_8$ films.

Abstract

Current-voltage ($I$-$V$) characteristics of Tl$_2$Ba$_2$CaCu$_2$O$_8$ thin films in zero magnetic field are measured and analyzed with the conventional Kosterlitz-Thouless-Berezinskii (KTB) approach, dynamic scaling approach and finite-size scaling approach, respectively. It is found from these results that the $I$-$V$ relation is determined by the vortex-unbinding mechanism with the KTB dynamic critical exponent $z=2$. On the other hand, the evidence of finite-size effect is also found, which blurs the feature of a phase transition.