Direct measurements of growing amorphous order and non-monotonic dynamic correlations in a colloidal glass-former

Nagamanasa, Hima K and Gokhale, Shreyas and Sood, AK and Ganapathy, Rajesh (2015) Direct measurements of growing amorphous order and non-monotonic dynamic correlations in a colloidal glass-former. In: NATURE PHYSICS, 11 (5). pp. 403-408.

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Abstract

The transformation of flowing liquids into rigid glasses is thought to involve increasingly cooperative relaxation dynamics as the temperature approaches that of the glass transition. However, the precise nature of this motion is unclear, and a complete understanding of vitrification thus remains elusive. Of the numerous theoretical perspectives(1-4) devised to explain the process, random first-order theory (RFOT; refs 2,5) is a well-developed thermodynamic approach, which predicts a change in the shape of relaxing regions as the temperature is lowered. However, the existence of an underlying `ideal' glass transition predicted by RFOT remains debatable, largely because the key microscopic predictions concerning the growth of amorphous order and the nature of dynamic correlations lack experimental verification. Here, using holographic optical tweezers, we freeze a wall of particles in a two-dimensional colloidal glass-forming liquid and provide direct evidence for growing amorphous order in the form of a static point-to-set length. We uncover the non-monotonic dependence of dynamic correlations on area fraction and show that this non-monotonicity follows directly from the change in morphology and internal structure of cooperatively rearranging regions(6,7). Our findings support RFOT and thereby constitute a crucial step in distinguishing between competing theories of glass formation.

Item Type:	Journal Article
Publication:	NATURE PHYSICS
Publisher:	NATURE PUBLISHING GROUP
Additional Information:	Copy right for this article belongs to the NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
Keywords:	FORMING LIQUIDS; SUPERCOOLED LIQUIDS; COOPERATIVE MOTION; LENGTH SCALES; TRANSITION; FACILITATION; SUSPENSIONS; RELAXATION
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	29 May 2015 05:44
Last Modified:	29 May 2015 05:44
URI:	http://eprints.iisc.ac.in/id/eprint/51603

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