Computer Simulations of Crystal Growth Using a Hard-Sphere Model

Abstract

A review of computer simulation studies on crystal growth in hard-sphere systems is presented. A historical view on the crystallization of hard spheres, including colloidal crystallization, is given in the first section. Crystal phase transition in a system comprising particles without bonding is difficult to understand. In the early days, therefore, many researchers did not accept such crystalline structures as crystals that should be studied in the field of crystal growth. In the last few decades, however, colloidal crystallization has drawn attention because in situ observations of crystallization process has become possible. Next, simulation studies of the crystal/fluid interface of hard spheres are also reviewed. Although colloidal crystallization has now been recognized in the crystal growth field, the stability of the crystal–fluid coexistence state has still not been satisfactorily understood based on a bond-breaking picture, because of an infinite diffuseness of the interfaces in non-bonding systems derived from this picture. Studies of sedimentary colloidal crystallization and colloidal epitaxy using the hard-sphere model are lastly reviewed. An advantage of the colloidal epitaxy is also presented; it is shown that a template not only fixes the crystal growth direction, but also improves the colloidal crystallization. A new technique for reducing defects in colloidal crystals through the gravity effect is also proposed.