title: Active crystals and their stability.
abstract: A recently introduced active phase field crystal model describes the formation of ordered resting and traveling crystals in systems of self-propelled particles. Increasing the active drive, a resting crystal can be forced to perform collectively ordered migration as a single traveling object. We demonstrate here that these ordered migrating structures are linearly stable. In other words, during migration, the single-crystalline texture together with the globally ordered collective motion is preserved even on large length scales. Furthermore, we consider self-propelled particles on a substrate that are surrounded by a thin fluid film. We find that in this case the resulting hydrodynamic interactions can destabilize the order.
authors.affiliation: Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany and Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Menzel
authors.affiliation: Department of Physics, Kyoto University, Kyoto 606-8502, Japan and Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Ohta
authors.affiliation: Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Löwen