We use colloidal systems to gain insight on dynamic phenomena at crystal interfaces. Recently we have designed a model system to study the plastic flow across well-defined grain boundaries in two-dimensional polycrystals. Specifically, we injected interstitial particles into colloidal monolayers and observed their pile-up, transmission and reflection at grain boundaries at single-particle resolution.

In another experiment, we studied the dynamics of a colloidal crystalline cluster driven across an incommensurate crystalline surface. We found that the direction of motion of the colloidal cluster does not necessarily follow the applied force but can be kinetically locked in directions determined by the Moiré pattern of the two contacting lattices. Such directional locking can be relevant for nanomanipulation and nanodevice assembly on crystalline surfaces.