Configurations and diffusion of point defects in two-dimensional colloidal crystals

Abstract

Configurations and diffusion of crystal defects are studied in a two-dimensional colloidal model system in the presence of an attraction. Monomer vacancies are immobile and have identical symmetry with the underlying triangular lattice. Both dimer vacancies and trimer vacancies have two different configurations and the configurations with higher symmetry are more stable. Dimer vacancies in the authors' our experiments exhibit the highest diffusivity, whereas the global diffusion of vacancies of larger clusters, such as trimer vacancies, is inhibited. Compared with previous studies, it is found that defect dynamics is strongly dependent on the nature of the interaction potential. © 2006 American Institute of Physics.