The Structure of the Amorphous (GeTe)1–x (Sb2Te3) x System and Implications for its Phase-Change Properties

Abstract

Abstract We describe structural features of ternary Ge-Sb-Te glasses based on anomalous X-ray scattering experiments for four different compositions along the pseudo-binary line (GeTe)1–x (Sb2Te3) x for 0 ≤ x ≤ 2 3 $0\leq x\leq\frac{2}{3}$ , which comprises technologically important phase-change materials. The data are analyzed with reverse Monte Carlo modeling. This way, detailed information on the local environments around all constituent elements are obtained and their evolution with the chemical composition is described. This approach gives a consistent view of the atomic scale structure of the amorphous networks in these compounds. Thereby, it is possible to derive the relationship between the relevant material properties and the determining structural features. In particular, it is shown that the optical contrast related to the phase change is associated with the evolution of the Ge-Te core network.