Spatial correlations in the relaxation of the Kob-Andersen modelE. Marinari1 and E. Pitard2
1 Dipartimento di Fisica, SMC and UdR1 of INFM, INFN Università di Roma "La Sapienza" - P.le Aldo Moro 2, 00185 Roma, Italy
2 Laboratoire des Verres (CNRS-UMR no. 5587), CC69 Université Montpellier 2 - 34095 Montpellier Cedex 5, France
received 24 May 2004; accepted in final form 5 November 2004
published online 17 December 2004
We describe spatio-temporal correlations and heterogeneities in a kinetically constrained glassy model, the Kob-Andersen model. The kinetic constraints of the model alone induce the existence of dynamic correlation lengths, that increase as the density increases, in a way compatible with a double-exponential law. We characterize in detail the trapping time correlation length, the cooperativity length, and the distribution of persistent clusters of particles. This last quantity is related to the typical size of blocked clusters that slow down the dynamics for a given density.
64.70.Pf - Glass transitions.
05.50.+q - Lattice theory and statistics (Ising, Potts, etc.).
61.20.Lc - Structure of liquids: Time-dependent properties; relaxation.
© EDP Sciences 2005