Ion transport in glass: Influence of glassy structure on spatial extent ofnonrandom ion hopping - art. no. 214203

On short time scales, the diffusion of mobile ions in glasses is nonrandom, i.e., the ions perform correlated forward-backward motions. By using linea r response theory, we show in detail how typical distances characterizing t he spatial extent of the nonrandom ionic diffusion can be derived from freq uency-dependent conductivity data when the Haven ratio is known. We compare the dependence of these typical distances on the alkali content in germana te, berate, and silicate glasses. In all glasses, the typical distances dec rease with increasing alkali oxide content. In the germanate and silicate g lasses, the decrease is, however, more pronounced than in the berates. This network former effect points to the influence of the network structure on the spatial extent of the nonrandom diffusion.