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Short-ranged attractions in jammed liquids: How cooling can melt a glass

Phillip L. Geissler·David R. Reichman
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Abstract

We demonstrate that an extended picture of kinetic constraints in glass-forming liquids is sufficient to explain dynamic anomalies observed in dense suspensions of strongly attracting colloidal particles. We augment a simple model of heterogeneous relaxation with static attractions between facilitating excitations, in a way that mimics the structural effect of short-ranged interparticle attractions. The resulting spatial correlations among facilitated and unfacilitated regions give rise to new relaxation mechanisms that account for non-monotonic dependence of relaxation times on attraction strength as well as logarithmic decay of density correlations in time. These unusual features are a simple consequence of spatial segregation of kinetic constraints, suggesting an alternative physical perspective on attractive colloids than that suggested by mode-coupling theory. Based on the behavior of our model, we predict a crossover from super-Arrhenius to Arrhenius temperature dependence as attractions become dominant at fixed packing fraction.

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Phillip L. Geissler, David R. Reichman. 2005-01-05. Short-ranged attractions in jammed liquids: How cooling can melt a glass. https://doi.org/10.1103/physreve.71.031206

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