Length-scale-dependent phase transition in BSCCO single crystals

TL;DR

This study investigates a length-scale-dependent phase transition in BSCCO single crystals, revealing that vortex loop unbinding and superconducting phase coherence transitions occur simultaneously but depend on the length scale, using electrical transport measurements.

Contribution

It demonstrates experimentally that the 3D/2D vortex and superconducting phase transitions are coupled and depend on length scale, advancing understanding of vortex dynamics in layered superconductors.

Findings

Vortex loop unbinding is thermally activated near the transition temperature.

The 3D/2D vortex transition coincides with the superconducting phase transition.

The transition is length-scale-dependent, indicating layer decoupling.

Abstract

Electrical transport measurements using a multiterminal configuration are presented, which prove that in BSCCO single crystals near the transition temperature in zero external magnetic field the secondary voltage is induced by thermally activated vortex loop unbinding. The phase transition between the bound and unbound states of the vortex loops was found to be below the temperature where the phase coherence of the superconducting order parameter extends over the whole volume of the sample. We show experimentally that 3D/2D phase transition in vortex dimensionality is a length-scale-dependent layer decoupling process and takes place simultaneously with the 3D/2D phase transition in superconductivity at the same temperature.