3 research outputs found
Dynamic Phases, Pinning, and Pattern Formation for Driven Dislocation Assemblies
We examine driven dislocation assemblies and show that they can exhibit a set of dynamical phases remarkably similar to those of driven systems with quenched disorder such as vortices in superconductors, magnetic domain walls, and charge density wave materials. These phases include pinned-jammed, fluctuating, and dynamically ordered states, and each produces distinct dislocation patterns as well as specific features in the noise fluctuations and transport properties. Our work suggests that many of the results established for systems with quenched disorder undergoing plastic depinning transitions can be applied to dislocation systems, providing a new approach for understanding pattern formation and dynamics in these systems
Domain and stripe formation between hexagonal and square ordered fillings of colloidal particles on periodic pinning substrates
Using large scale numerical simulations, we examine the ordering of colloidal particles on square periodic
two-dimensional muffin-tin substrates consisting of a flat surface with localized pinning sites. We show
that when there are four particles per pinning site, the particles adopt a hexagonal ordering, while for
five particles per pinning site, a square ordering appears. For fillings between four and five particles per
pinning site, we identify a rich variety of distinct ordering regimes, including disordered grain
boundaries, crystalline stripe structures, superlattice orderings, and disordered patchy arrangements. We
characterize the different regimes using Voronoi analysis, energy dispersion, and ordering of the
domains. We show that many of the boundary formation features we observe occur for a wide range of
other fillings. Our results demonstrate that grain boundary tailoring can be achieved with muffin-tin
periodic pinning substrates