Abstract
T. Palberg: „Crystallization in binary mixtures of charged colloidal spheres”
Institute of Physics, Johannes-Gutenberg-Universität Mainz
The phase behaviour of binary hard sphere mixtures has recieved a lot of attention and their crystallization into compound structures has been studied both experimentally and theoretically. By contrast much less is known about the structures formed in binary charged sphere mixtures. We here report a systematic study of their phase behaviour as a function of charge and size ratio. Like metals, charged spheres own a soft repulsive potential and form a large variety of phase diagram types. Rather than compound formation, the crystallization into substitutional alloys of body cenred cubic structure is observed. For a selected eutectic mixture we further give a detailed account of the crystallization mechanisms, which are noticeably influenced by gravity and the presence of the cell walls.