  Freestanding tubular crystals offer a general description of crystalline
order on deformable surfaces with cylindrical topology, such as single-walled
carbon nanotubes, microtubules, and recently reported colloidal assemblies.
These systems exhibit a rich interplay between the crystal's helicity on its
periodic surface, the deformable geometry of that surface, and the motions of
topological defects within the crystal. Previously, in simulations of tubular
crystals as elastic networks, we found that dislocations in nontrivial patterns
can co-stabilize with kinks in the tube shape, producing mechanical
multistability. Here, we extend that work with detailed Langevin dynamics
simulations, in order to explore defect dynamics efficiently and without the
constraints imposed by elastic network models. Along with the predicted
multistability of dislocation glide, we find a variety of irreversible defect
transformations, including vacancy formation, particle extrusions, and
"reactions" that reorient dislocation pairs. Moreover, we report spontaneous
sequences of several such defect transformations, which are unique to tubular
crystals. We demonstrate a simple method for controlling these sequences
through a time-varying external force.

Soft Condensed Matter;Materials Science;Biological Physics;Computational Physics