Colloquium

Impact of structural ordering in supercooled liquids on vitrification and crystallization

Speaker: Hajime Tanaka (The University of Tokyo, Japan)

Date and time

Abstract

When a liquid is cooled, it will be either crystallized or vitrified, depending upon the cooling rate. However, it has been unclear what physical factors control the fate of the liquid. Upon cooling, structural order develops in a supercooled liquid to lower the free energy. We find that the growth of static structural order leads to slow glassy dynamics in fragile liquids. This structural ordering is a consequence of many-body correlations and thus difficult to detect by a two-body density correlator except for orderings involving translational ordering (e.g., the formation of tetrahedral structures in silica and water). If it is compatible with crystal symmetry, it acts as a precursor for crystal nucleation and plays an essential role in selecting polymorphs. We also study the glass-forming ability of systems with competing orderings and find that the enhancement of glass-forming ability is caused by an increase in the structural contrast between liquid and crystal. These results suggest that structural order developed in a supercooled liquid controls slow glassy dynamics, crystallization, and glass-forming ability.

Hajime Tanaka

Hajime Tanaka obtained his bachelor’s, Master’s, and PhD degrees from the Department of Applied Physics, the University of Tokyo, Japan, (1977, 1979, and 1982). He is currently Professor Emeritus, the University of Tokyo, and Senior Program Advisor at Research Center for Advanced Science and Technology, the University of Tokyo. After getting his PhD, he became Assistant Professor at the Department of Applied Physics, the University of Tokyo. He moved to the Institute of Industrial Science, the University of Tokyo in 1989 and was Professor from 1999-2020 until his retirement. He was a visiting scientist at AT&T Bell Laboratories in 1987, Cavendish Laboratory, the University of Cambridge, and Ecole Normale Superior at Paris in 1997. He has worked on a wide range of problems related to soft matter physics and liquid matter physics both experimentally and theoretically. He has been intrigued by the general behavior of a system having spatiotemporally hierarchical structures and the commonality between soft matter and liquid matter in that respect. More specifically, he has been interested in pattern formation and nonlinear rheology of soft matter, physics of water, liquid-liquid transition, glass transition, and crystallization. He has published some 300 papers in refereed Journals.
Awards for research have included the Award of the Society of Polymer Science, Japan (1997), the Humboldt Research Award (Alexander von Humboldt Foundation, Germany) (2006), and The Liquid Crystal Society, Top Paper Award (2010). He became a Fellow of the Institute of Physics in 2007. He has served on the editorial boards of several scientific journals, including Journal of Physics: Condensed Matter, Molecular Physics, Soft Matter, Science Advances, and Journal of Chemical Physics.