Characteristics of slow and fast ion dynamics in a lithium metasilicate glass

Molecular dynamics simulations of lithium metasilicate (Li(2)SiO(3)) glass have been performed. The motion of lithium ions is divided into slow (A) and fast (B) categories in the glassy state. The waiting time distribution of the jump motion of each component shows power law behavior with different exponents. Slow dynamics are caused by localized jump motions and the long waiting time. On the other hand, the fast dynamics of the lithium ions in Li(2)SiO(3) are characterized as Lévy flight caused by cooperative jumps. Short intervals of jump events also occur in the fast dynamics in the short time region. Both the temporal and spatial terms contribute to the dynamics acceleration and the heterogeneity caused by these two kinds of dynamics is illustrated. The slow dynamics characteristics of the "glass transition" and in the "mixed alkali effect" are discussed.