Dynamic regimes and spontaneous symmetry breaking for driven colloids on triangular substrates

For collectively interacting repulsive colloids driven on triangular substrates, we show that a number of distinct dynamical regimes arise as a function of the drive strength. Additionally, we show that for certain directions of drive a spontaneous-symmetry-breaking phenomenon occurs where all the colloids can flow in one of two directions that are not aligned with the external drive. Along these directions, the flow is highly ordered, in contrast to the disordered flow that occurs when the colloids move in the direction of the drive. We also find unusual hysteretic properties that arise due to the symmetry-breaking properties of the flows.