The large optical contrast between crystalline and amorphous phases of phase change memory materials is shown to arise from a large difference in the optical matrix elements. These are enhanced in the crystal by aligned rows of resonantly bonded p orbitals. Amorphous phases have normal-sized matrix elements due to an absence of this order, irrespective of coordination number. This is a more general description of local order differences between the crystalline and amorphous phases, which applies even when coordinations in the amorphous phases exceed the 8-N value.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 18 Feb 2010|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics