Direct Evidence for Intrinsically Broken Chemical Ordering in Melt-Quenched Glasses

Abstract

The chalcogen site in bulk glasses of Ge${\mathrm{Se}}_{2}$ and Ge${\mathrm{S}}_{2}$ has been probed via nuclear quadrupole interactions with use of $^{129}\mathrm{Te}^{m}$ impurity atoms as parent in $^{129}\mathrm{I}$ M\"ossbauer emission spectroscopy. Two distinct types of chalcogen sites are observed and are shown to provide direct evidence for intrinsically broken chemical ordering in these network glasses. The composition dependence of the site parameters in pseudobinary-alloy glasses indicates the presence of characteristic large clusters rather than a continuous random network.