Simulation of phase transformations in phase-change media

We report progress towards the development of a comprehensive simulation capability of the phase-transformations in a Ge/sub 2/Sb/sub 3/Te/sub 5/ film phase change optical storage media. Our ultimate goal is to have an approach which incorporates both nucleation and growth processes in a unified manner. In the first stages, we have developed a nucleation theory of the amorphous-to-crystallization phase transformation. We have also begun to build a theory of the growth (or motion) of crystalline-amorphous boundaries in the presence of a laser field, thus initiating the study of growth processes.