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.