Moving Vortex Phases, Dynamical Symmetry Breaking, and Jamming for Vortices in Honeycomb Pinning Arrays

摘要

We show using numerical simulations that vortices in honeycomb pinning arrayscan exhibit a remarkable variety of dynamical phases that are distinct fromthose found for triangular and square pinning arrays. In the honeycomb arrays,it is possible for the interstitial vortices to form dimer or higher n-merstates which have an additional orientational degree of freedom that can leadto the formation of vortex molecular crystals. For filling fractions wheredimer states appear, a novel dynamical symmetry breaking can occur when thedimers flow in one of two possible alignment directions. This leads totransport in the direction transverse to the applied drive. We show thatdimerization produces distinct types of moving phases which depend on thedirection of the driving force with respect to the pinning lattice symmetry.When the dimers are driven along certain directions, a reorientation of thedimers can produce a jamming phenomenon which results in a strong enhancementin the critical depinning force. The jamming can also cause unusual effectssuch as an increase in the critical depinning force when the size of thepinning sites is reduced.