title: Dynamic heterogeneity of relaxations in glasses and liquids
abstract: We report an investigation of the heterogeneity in supercooled liquids and glasses using the non-Gaussianity parameter. We simulate selenium and a binary Lennard-Jones system by molecular dynamics. In the non-Gaussianity three time domains can be distinguished: an increase on the ps scale due to the vibrational (ballistic) motion of the atoms, followed by a growth, due to local relaxations ( beta relaxation) at not too high temperatures, and finally a slow drop at long times. The non-Gaussianity follows in the intermediate time domain a sqrt[t] law. This is explained by collective hopping and dynamic heterogeneity. We support this finding by a model calculation.
authors.affiliation: Institut fur Festkorperforschung, Forschungszentrum Julich, D-52425 Julich, Germany.
authors.initials: D
authors.lastname: Caprion
authors.initials: J
authors.lastname: Matsui
authors.initials: HR
authors.lastname: Schober