Dynamic Phases and Combing Effects for Elongated Particles Moving Over Quenched Disorder

Abstract

We consider a two-dimensional system of elongated particles driven over a random quenched disorder landscape. For varied pinning site density, external drive magnitude, and particle elongation, we find a wide variety of dynamic phases, including random structures, stripe or combed phases with nematic order, and clogged states. The different regimes can be identified by examining nematic ordering, cluster size, number of pinned particles, and transverse diffusion. In some regimes we find that the pinning can enhance the particle alignment, producing a nonmonotonic signature in the nematic ordering with a maximum at a particular combination of pinning density and drive. The optimal nematic occurs when a sufficient number of particles can be pinned, generating a local shear and leading to what we call a combing effect. At high drives, the combing effect is reduced when the number of pinned particles decreases. For stronger pinning, the particles form a heterogeneous clustered or clogged state that depins into a fluctuating state with high diffusion.

6 pages, 7 figures

References in corpus (12)

• Swarming and swirling in self-propelled polar granular rods
• Minimal model for active nematics: quasi-long-range order and giant fluctuations
• Quantized Transport for a Skyrmion Moving on a Two-Dimensional Periodic Substrate
• Dynamic Phases of Active Matter Systems with Quenched Disorder
• Dynamics of active filaments in porous media
• Rheology of dense granular flows for elongated particles
• Crowding-Enhanced Diffusion: An Exact Theory for Highly Entangled Self-Propelled Stiff Filaments
• Entangled Dynamics of a Stiff Polymer
• Collective Transport for Active Matter Run and Tumble Disk Systems on a Traveling Wave Substrate
• Motile topological defects hinder dynamical arrest in dense liquids of active ellipsoids
• Discharge of elongated grains from silo with rotating bottom
• Driven Superconducting Vortex Dynamics in Systems with Two-Fold Anisotropy in the Presence of Pinning