Entanglement of Solid Vortex Matter: A Boomerang Shaped Reduction Forced by Disorder in Interlayer Phase Coherence in Bi2Sr2CaCu2O8+y

TL;DR

This paper provides evidence of a complex entangled vortex solid state in a layered superconductor with disorder, revealing unique temperature-dependent coherence behaviors and supporting the existence of a splayed-glass phase.

Contribution

It demonstrates the formation of a splayed-glass vortex state with boomerang-shaped coherence reentrance and distinct critical current scaling in Bi2Sr2CaCu2O8+y.

Findings

Enhanced interlayer coherence at high temperatures due to defect-induced recoupling.

Reentrant boomerang-shaped temperature dependence of coherence at low temperatures.

Opposing field and time dependencies of in-plane and out-of-plane critical currents.

Abstract

We present evidence for entangled solid vortex matter in a glassy state in a layered superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+y}$ containing randomly splayed linear defects. The interlayer phase coherence--probed by the Josephson plasma resonance--is enhanced at high temperatures, reflecting the recoupling of vortex liquid by the defects. At low temperatures in the vortex solid state, the interlayer coherence follows a boomerang-shaped reentrant temperature path with an unusual low field decrease in coherence, indicative of meandering vortices. We uncover a distinct temperature scaling between in-plane and out-of-plane critical currents with opposing dependencies on field and time, consistent with the theoretically proposed "splayed-glass" state.