Are steadily moving crystals unstable?

Abstract

We study the dynamics of small fluctuations about the uniform state of a crystal moving through a dissipative medium, e.g., a sedimenting colloidal crystal or a moving flux lattice, using a set of continuum equations for the displacement fields, and a one-dimensional driven lattice-gas model for the coupled concentration and tilt fields. For the colloidal crystal we predict a continuous nonequilibrium phase transition to a clumped state above a critical Péclet number.