Title
Structural ordering of supercooled liquids and its link to crystallization
Speaker
Hajime Tanaka (University of Tokyo)
Abstract
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.
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