Crystalline–amorphous and amorphous–amorphous transitions in phase-change materials

The transition from the crystalline state to amorphous state and back has been studied in the particular case of the GeSb2Te4 phase-change material by a computer simulation procedure. Modelling at the nanoscale indicates specific structural characteristics, especially the multiplicity of the amorphous phase as opposite to the uniqueness of the crystalline phase. In the particular case of the Si12Ge10As30Te48 switching glass two types of ordering have been pointed out and characterized.