An anomalous X-ray scattering study on glassy superionic conductor (As2Se3)1−x(CuI)x using a third-generation synchrotron radiation facility

Anomalous X-ray scattering experiments on glassy superionic conductor (As2Se3)0.4(CuI)0.6 were performed at energies close to the As, Se, and Cu K edges using a new detecting system and a third-generation synchrotron radiation facility. The detecting system was composed of a graphite-crystal energy-analyzer and a NaI(Tl) detector on a 40-cm-long arm. The overall energy resolution was about 60 eV, which can discriminate the elastic signal from the fluorescence and Compton contributions, and a sufficient number of scattered X-ray photons were acquired within a reasonable data collection time. The differential structure factors, ΔiS(Q), were obtained from the detailed analyses, indicating that ΔAsS(Q) and ΔSeS(Q) are similar to those of glassy As2Se3 except at the prepeak position, and ΔCuS(Q) that in liquid CuI. From these findings, it can be concluded that a pseudo-binary mixture of the As2Se3 network matrix and CuI-related conduction pathways would be a good structural model for this superionic glass.