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

Abstract

While the transformation of flowing liquids into rigid glasses is omnipresent, a complete understanding of vitrification remains elusive. Of the numerous approaches aimed at solving the glass transition problem, the Random First-Order Theory (RFOT) is the most prominent. However, the existence of the underlying thermodynamic phase transition envisioned by RFOT remains debatable, since its key microscopic predictions concerning the growth of amorphous order and the nature of dynamic correlations lack experimental verification. Here, by using holographic optical tweezers, we freeze a wall of particles in an equilibrium configuration of a 2D colloidal glass-forming liquid and provide direct evidence for growing amorphous order in the form of a static point-to-set length. Most remarkably, 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 of cooperatively rearranging regions, as predicted by RFOT. Our findings suggest that the glass transition has a thermodynamic origin.

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• Direct evidence of void induced structural relaxations in colloidal glass formers
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• Block Analysis for the Calculation of Dynamic and Static Length Scales in Glass-Forming Liquids
• Aging near rough and smooth boundaries in colloidal glasses
• Dynamics in two-dimensional glassy systems of crowded Penrose kites
• Concentrated suspensions of Brownian beads in water: dynamic heterogeneities trough a simple experimental technique
• Influence of an amorphous wall on the distribution of localized excitations in a colloidal glass-forming liquid
• Surface melting of a colloidal glass
• Probing the Local Response of Glass-forming Liquids by Laser Excitations
• Trapping/Pinning of colloidal microspheres over glass substrate using surface features
• Static self-induced heterogeneity in glass-forming liquids: Overlap as a microscope
• Formation of a transient amorphous solid in low density aqueous charged sphere suspensions