Dresden 2003 – wissenschaftliches Programm
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M: Metallphysik
M 38: Flüssige und amorphe Metalle III
M 38.1: Vortrag
Donnerstag, 27. März 2003, 10:15–10:30, IFW D
Hopping in a Supercooled Lennard-Jones Liquid: Metabasins, Waiting Time Distribution, and Diffusion — •Andreas Heuer1 and Burkhard Doliwa2 — 1Institute of Physical Chemistry, Schlossplatz 4/7, D-48149 Münster — 2Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz
We investigate the jump motion among potential energy minima of a Lennard-Jones model glass former by extensive computer simulation. From the time series of minima energies, it becomes clear that the energy landscape is organized in superstructures, called metabasins. We show that diffusion can be pictured as a random walk among metabasins, and that the whole temperature dependence resides in the distribution of waiting times. The waiting-time distributions exhibit algebraic decays: τ−1/2 for very short times and τ−α for long times, where α≈2 near Tc. We demonstrate that solely the waiting times in the very stable basins account for the temperature dependence of the diffusion constant. If we had ignored the existence of metabasins, i.e. worked with a single-basin description, the overall picture would have become much more complicated.