  We show that a remarkable variety of dynamical phenomena, including
switching, polarization, symmetry locking, and dynamically induced pinning, can
occur for vortices in type-II superconductors in the presence of a honeycomb
pinning array and an ac or combined ac and dc drive. These effects occur at the
second matching field where there are two vortices per pinning site, and arise
due to the formation of vortex dimer states in the interstitial regions of the
honeycomb array. The orientation of the pinned and moving vortex dimers can be
controlled externally by the application of a drive. We term this a
polarization effect and demonstrate that it can lock or unlock the vortex
motion into different symmetry directions of the underlying pinning lattice. If
the moving vortices are locked into one direction, the motion can be switched
into a different direction by applying an additional bias drive, producing
sharp jumps in the transverse and longitudinal velocities. Further, the dc
vortex motion in one direction can be controlled directly by application of a
force in the perpendicular direction. When the moving dimers reorient, we find
a remarkable dynamical pinning effect in which the dimers jam when they become
perpendicular to the easy flow direction of the pinning lattice. Since
application of an external field can be used to switch off the vortex flow, we
term this a jamming transistor effect. These effects do not occur in triangular
pinning arrays due to the lack of the n-merization of the vortices in this
case. The switching and dynamical pinning effects demonstrated here may be
useful for the creation of new types of fluxtronic devices.
