Macroscopic Phase Coherence of Defective Vortex Lattices in Two Dimensions

TL;DR

This paper theoretically investigates how pinned vortices in a two-dimensional superfluid lattice can confine dislocations, thereby maintaining macroscopic phase coherence at low temperatures despite defects.

Contribution

It introduces a model showing that sparse pinned vortices can confine dislocations, preventing plastic creep and preserving phase coherence in 2D vortex lattices.

Findings

Pinned vortices confine dislocations along glide planes.

Plastic creep is impeded in the presence of pinned vortices.

Macroscopic phase coherence is maintained at low temperatures.

Abstract

The superfluid density is calculated theoretically for incompressible vortex lattices in two dimensions that have isolated dislocations quenched in by a random arrangement of pinned vortices. The latter are assumed to be sparse and to be fixed to material defects. It is shown that the pinned vortices act to confine a single dislocation of the vortex lattice along its glide plane. Plastic creep of the two-dimensional vortex lattice is thereby impeded, and macroscopic phase coherence results at low temperature in the limit of a dilute concentration of quenched-in dislocations.