  We examine the dynamics of a single colloidal particle driven through a
colloidal lattice which can distort in response to the driven particle. We find
a remarkably rich variety of dynamical locking phenomena as we vary the angle
of the applied drive with respect to the orientation of the colloidal lattice.
When the driven colloid locks to certain lattice symmetry directions, its
motion is not necessarily aligned with the drive. Applying a transverse force
to the driven particle can result in either increased or decreased drag in the
driving direction, depending on the angle of the drive. The dynamical locking
produces anomalies in both the longitudinal and the transverse velocity vs
driving force curves, including steps and regimes of negative differential
resistance. As the interaction of the driven particle with the surrounding
lattice increases, significant distortion or dislocations in the surrounding
media occur, and as a result the directional locking is enhanced. We compare
these results to those obtained for driving particles over fixed substrates,
and show that a far richer variety of behaviors occurs when the underlying
lattice is allowed to distort. We discuss how this system can be used for
particle species segregation when the onset of different locking angles occurs
at different drives for varied particle sizes. We also show that the most
pronounced locking phases should be observable at temperatures up to the
melting transition of the colloidal lattice.
