Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 14: Poster: Glasses I (jointly with DY)
CPP 14.16: Poster
Dienstag, 27. März 2012, 18:15–20:15, Poster A
Aging and elementary relaxation processes in amorphous solids — •Nima Hamidi Siboni1,3, Fathollah Varnik2, and Dierk Raabe3 — 1Aachen Institute for Computational Engineering Science, Aachen, Germany — 2The Interdisciplinary Centre for Advanced Materials Simulation, Bochum, Germany — 3Max-Planck Institut für Eisenforschung, Düsseldorf, Germany
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, ξ(t1), and the waiting time between two successive events, φ(τ) is modified upon aging. This is at first sight not surprising since these two distributions are known to satisfy the relation ξ(t1)=∫t1∞ φ(t′)t′ dt′ /⟨τ⟩φ, where ⟨τ⟩φ=∫0∞ φ(t′)t′dt′ is the mean waiting time [3]. Recent simulation studies of this issue, however, report that only ξ(t1) changes upon aging, while φ(τ) seems to remain stationary [4]. This unexpected behavior has been attributed to a possible power-law tail of φ(τ) and the resulting divergence of ⟨τ⟩. We thoroughly study this issue and propose possible 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).