Field-driven topological glass transition in a model flux line lattice

TL;DR

This paper investigates how a layered high-temperature superconductor's flux line lattice becomes unstable and transitions to a disordered phase under high magnetic fields, driven by topological defects and lattice softening.

Contribution

It introduces a model explaining the field-driven topological glass transition in flux line lattices, supported by simulations and relevant to experimental observations.

Findings

Identification of a critical magnetic field causing lattice instability.

Demonstration of a transition from crystalline to disordered phase.

Correlation with neutron diffraction experiments on Bi2Sr2CaCu2O8 crystals.

Abstract

We show that the flux line lattice in a model layered HTSC becomes unstable above a critical magnetic field with respect to a plastic deformation via penetration of pairs of point-like disclination defects. The instability is characterized by the competition between the elastic and the pinning energies and is essentially assisted by softening of the lattice induced by a dimensional crossover of the fluctuations as field increases. We confirm through a computer simulation that this indeed may lead to a phase transition from crystalline order at low fields to a topologically disordered phase at higher fields. We propose that this mechanism provides a model of the low temperature field--driven disordering transition observed in neutron diffraction experiments on ${\rm Bi_2Sr_2CaCu_2O_8\, }$ single crystals.