Lattice deformations and plastic flow through bottlenecks in a two-dimensional model for flux pinning in type-II superconductors

The deformations of a 2D vortex lattice pinned by a random potential are studied by a molecular-dynamics annealing method. All but very weak potentials produce a highly defective lattice, consisting of trapped lattice regions separated by channels in which the vortices flow plastically. It is argued that this type of deformation is the cause of the observed restricted applicability of collective pinning theory.