Colloquium on November 11th, 2006


Frans A. Spaepen
Harvard University

Colloidal Systems: 'Analog computers' for simulating the dynamics of crystals and glasses

Colloidal particles in a fluid interact by central potentials (hard sphere or electrostatic). At large packing fractions they form phases similar to those formed by atoms in condensed matter: liquids, crystals and glasses. Since the particles are large and slow, they can be tracked in time and in three-dimensional space by confocal microscopy. Colloidal systems, therefore, are highly efficient "analog computers" for the study of the dynamics of complex multiparticle phenomena in condensed matter. A number of examples are presented: crystal nucleation, coherency dislocations in epitaxial growth, indentation of single crystals, plastic shear of glasses, and the structure of grain- and twin boundaries.