Colloidal Crystals: Many-Body Physics Both Beautiful and Fun

Colloidal suspensions of uniform highly charged submicron polystyrene spheres are ideal for the study of complex phase transformation behavior in condensed matter as the time and distance scales of the system are readily available with visible light and video technology. We have observed a number of different ordered phases of colloids in three dimensions and in thin slabs, and have studied their melting behavior in two dimensions as well as surface reconstructions of three dimensional crystals. By digitizing real-space images of the colloid, we can follow individual microscopic particle motions in real time so that the system can be used as an "analog" molecular dynamics computer with far longer samples and equilibrium times possible than presently possible in computer simulations. We have had wonderful fun doing these experiments and learned a great deal about the physics of many-body behavior in the process. A Videotape will be shown.