Field-Driven Topological Glass Transition in a Model Flux Line Lattice.

We show that the flux line lattice in a model layered high temperature superconductor 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 propose that this mechanism provides a model of the low temperature field-driven disordering transition observed in neutron diffraction experiments on Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals. {copyright} {ital 1996 The American Physical Society.}