Mechanism of colloidal sphere self-assembly

Abstract

Colloidal suspensions have been widely employed as model systems in studying fundamental problems of condensed matter physics. This kind of studies has offered deep insight into the understanding of melting, glass transition and nucleation. Here, the mechanism of crystallization is studied in a two-dimensional (2D) colloidal system driven by an alternating electric field. It was found that the initial structure of crystal nuclei is distinct from that of the bulk crystal and that crystal nuclei experience a continuous structural transition in the subsequent growth. Another alternative route for crystal nucleation is multistep crystallization which occurs via a metastble amorphous phase. Crystalline nuclei are then nucleated from the metastable amorphous phase. After nucleation, crystallization enters into the second stage, that is crystal growth, by which crystal nuclei develop into bulk crystals. In this study, the effect of long-range attraction on the kinetics of crystal growth is investigated. Since defects occur inevitably in crystals, in this study we also investigate the dynamics of crystal defects.