The shapes of cooperatively rearranging regions in glass-forming liquids

By Jacob D. Stevenson, J. Schmalian, Peter G. Wolynes. 2005

253 citations recorded by the source corpus.

The cooperative rearrangement of groups of many molecules has long been thought to underlie the dramatic slowing of liquid dynamics on cooling towards the glassy state. For instance, there exists experimental evidence for cooperatively rearranging regions (CRRs) on the nanometre length scale near the glass transition. The random first-order transition (RFOT) theory of glasses predicts that, near the glass-transition temperature, these regions are compact, but computer simulations and experiments on colloids suggest CRRs are string-like. Here, we present a microscopic theory within the framework of RFOT, which unites the two situations. We show that the shapes of CRRs in glassy liquids should change from being compact at low temperatures to fractal or ‘stringy’ as the dynamical crossover temperature from activated to collisional transport is approached from below. This theory predicts a correlation of the ratio of the dynamical crossover temperature to the laboratory glass-transition temperature, and the heat-capacity discontinuity at the glass transition. The predicted correlation quantitatively agrees with experimental results for 21 materials.

Subfields: Ceramics and Composites, Condensed Matter Physics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/fff3a9f8309e27f513462f35ac41aa1810cfbb56

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In Ceramics and Composites

In Condensed Matter Physics

In Materials Chemistry

Citations in the corpus

Theoretical perspective on the glass transition and amorphous materials (2010, background): “In fact, this analogy has been fruitfully explored, for instance to describe real space features of dynamic heterogeneity near TMCT (Kirkpatrick et al., 1989; Stevenson et al., 2006; Cavagna, 2009).”
The role of local structure in dynamical arrest (2014, background): “Theoretical work within the RFOT picture suggests that the picture of a unique length to characterise dynamic motion might obscure a change in the nature of co-operatively re-arranging regions [490].”
The elastic properties, elastic models and elastic perspectives of metallic glasses (2012, background): “Experimental evidence [82,220,613,614] shows that the STZ hypothesis is consistent with the classical thermodynamic theories of liquids and glasses based on the concept of potential energy landscapes, PEL.”
Non-monotonic temperature evolution of dynamic correlations in glass-forming liquids (2011, background): “have suggested that around T c the cooperative domains should indeed change shape, in that they have an open structure above T c and a more compact structure below T c (ref&nbs”
Measurement of growing dynamical length scales and prediction of the jamming transition in a granular material (2007, background): “theory and the random first-order theory of glasse”
Thermodynamic signature of growing amorphous order in glass-forming liquids (2008, background): “Coherent amorphous order droplets should therefore be fractal around TMC and compact below [30], which suggests an increase of the effective value of ν as T decreases.”