Polycrystalline solidification in a quenched 2D colloidal system

Abstract

We investigate a two-dimensional colloidal system when quenched from the isotropic fluid phase into the crystalline phase. In thermal equilibrium one finds two continuous phase transitions with a hexatic phase in between the fluid and the crystalline phase. Here, no indications of this anisotropic fluid are observed if the system is driven out of equilibrium. Therefore we investigate whether a nucleation process may describe the scenario. To identify the crystallites a criterion based on the local bond-order field is introduced. With this at hand the growth of the crystallites is investigated. At early times, small crystallites start to grow in the supercooled isotropic phase and later, when the crystallites start to touch each other, the small ones are merged into the bigger crystallites due to a ripening process.