ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Aging and elementary relaxation processes in amorphous solids

Date: 27.03.2012
Time: 10:00 a.m.
Place: DPG Spring Meeting 2012, Berlin, Germany

Nima Hamidi Siboni, RWTH Aachen, Aachen, Germany
Dierk Raabe, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
Fathollah Varnik

Aging affects both dynamical [1] and mechanical (e.g., yield stress [2]) properties of amorphous solids. We study here aging effects on the distribution of elementary relaxation processes for the case of a binary Lennard-Jones glass. Both the distribution of first relaxation events and the waiting time between two successive events is modified upon aging. This is at first sight
not surprising since the first passage time can be obtained from the integration of the waiting time distribution [3]. Recent simulation studies of this issue, however, report that only the first passage time changes upon aging, while the waiting time seems to remain stationary [4]. This unexpected behavior has been attributed to a possible power-law tail of the waiting time distribution and the resulting divergence of its first moment, the average waiting time. We thoroughly study this issue and propose alternative explanations of this apparent discrepancy [5].
[1] W. Kob, J.-L. Barrat, Phys. Rev. Lett. 78, 4581 (1997).
[2] F. Varnik, L. Bocquet, J.-L. Barrat, J. Chem. Phys. 120, 2788 (2004).
[3] O. Rubner, A. Heuer 78, 011504 (2008).
[4] M. Warren, J. Rottler 88, 58005 (2009).
[5] N. Hamidi Siboni, D. Raabe, F. Varnik (in preparation).

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