Abstract
The diffusivity of tagged particles is demonstrated to be heterogeneous on time scales comparable to or less than the stress relaxation time in a highly supercooled model liquid. The particle motions in the relatively active regions dominantly contribute to the mean square displacement, giving rise to a diffusion constant larger than the Stokes-Einstein value. The van Hove self-correlation function is shown to have a large tail which can be scaled in terms of for . Its presence indicates heterogeneous diffusion in the active regions. However, the diffusion process becomes homogeneous on time scales longer than the life time of the heterogeneity structure .
- Received 13 July 1998
DOI:https://doi.org/10.1103/PhysRevLett.81.4915
©1998 American Physical Society