Structural ordering of supercooled liquids and its link to crystallization


Hajime Tanaka (University of Tokyo)


The origin of slow dynamics near glass transition and the mechanism of crystal nucleation are two unsolved fundamental problems associated with the metastable supercooled state of a liquid. So far these phenomena have been considered rather independently, however, we have revealed an intimate link between them. Recently we found that crystal-like bond orientational order develops in the supercooled state of (nearly) single-component systems such as spin liquids and weakly polydisperse colloidal liquids. In these liquids, low free-energy configurations in a supercooled liquid have a link to the rotational symmetry which is going to be broken upon crystallization. We argue that this is a direct consequence of that the same free energy governs both glass transition and crystallization at least in this type of liquids. We found that it is such structural ordering at least in this type of liquids that causes glassy slow dynamics and dynamic heterogeneity. Furthermore, we revealed that such structural order also plays a crucial role in crystal nucleation: Crystallization is a process of the enhancement of spatial coherence of crystal-like bond orientational order and ‘not’ driven by translational order at least in the nucleation stage. These results clearly indicate that the theoretical description at the two-body level is not enough for the description of these phenomena and it is crucial to take into account many body correlations, particularly, bond orientational correlations. We argue that there is an intrinsic link between glass transition and crystallization at least in quasi-single-component systems.

Designed by CSS.Design Sample