Dynamics of Dislocations in Thin Colloidal Crystals

Abstract

Suspensions of µm-size colloidal particles form structures similar to those formed by atoms (vapor, liquid, glass, crystal). Since they can be observed optically in real time on the particle scale, colloids can be used to study the dynamics of these structures. Large single crystals of hard-sphere-like colloidal particles can be grown in the f.c.c. structure on a (100) template. They contain vacancies, stacking faults and dislocations. The stacking faults are extended because of their negligible energy and are bounded by Shockley partial dislocations. Dislocations are introduced by lattice mismatch at the template or by deformation (e.g., indentation). Their strain fields are imaged by laser diffraction microscopy (geometrically similar to electron microscopy) and their cores by confocal optical microscopy. The critical thickness of the epitaxial crystal, the rate of introduction of the interfacial dislocations and their offset from the template are accurately predicted by continuum dislocation theory.