Short and Long-Range Order in Phase Change Materials

Abstract

This chapter offers a brief historical review of phase change materials as well as an overview of more recent findings. The chapter mainly focuses on the prototypical phase change materials in the Ge-Sb-Te and doped Sb-Te systems as these are currently the two composition spaces that are being applied both in the current generation of optical storage as well as future generations of electrical memory. In many ways, the structures of both the crystalline and amorphous phase change materials are atypical; the crystalline phase is often metastable, while the amorphous phase defies description as a typical random covalent network. We explore both long and short-range order of some prototypical compositions in the hope of providing a baseline from which deeper interpretations can be made.