Revealing Hidden Structural Order Controlling Both Fast and Slow Glassy Dynamics in Supercooled Liquids

Abstract Few questions in condensed matter science have proven as difficult to unravel as the interplay between structure and dynamics in supercooled liquids. To explore this link, much research has been devoted to pinpointing local structures and order parameters that correlate strongly with dynamics. Here we use an unsupervised machine learning algorithm to identify structural heterogeneities in three archetypical glass formers—without using any dynamical information. In each system, the unsupervised machine learning approach autonomously designs a purely structural order parameter within a single snapshot. Comparing the structural order parameter with the dynamics, we find strong correlations with the dynamical heterogeneities. Moreover, the structural characteristics linked to slow particles disappear further away from the glass transition. Our results demonstrate the power of machine learning techniques to detect structural patterns even in disordered systems, and provide a new way forward for unraveling the structural origins of the slow dynamics of glassy materials.

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Structural order as a genuine control parameter of dynamics in simple glass formers

Nature Communications ◽

10.1038/s41467-019-13606-3 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 9

Author(s):

Hua Tong ◽

Hajime Tanaka

Keyword(s):

Glass Transition ◽

Order Parameter ◽

Liquid Structure ◽

Coarse Grained ◽

Glassy Dynamics ◽

Slowing Down ◽

Structural Order ◽

Particle Level ◽

Complex Structural ◽

Unified Description

AbstractGlass transition is characterised by drastic dynamical slowing down upon cooling, accompanied by growing spatial heterogeneity. Its rationalisation by subtle changes in the liquid structure has been long debated but remains elusive, due to intrinsic difficulty in detecting the underlying complex structural ordering. Here we report that structural order parameter characterising local packing capability can well describe the glassy dynamics not only macroscopically but also microscopically, no matter whether it is driven by temperature or density. A Vogel-Fulcher-Tammann (VFT)-like relation is universally identified between the structural relaxation time and the order parameter for supercooled liquids with isotropic interactions. More importantly, we find such an intriguing VFT-like relation to be statistically valid even at a particle level, between spatially coarse-grained structural order and microscopic particle-level dynamics. Such a unified description of glassy dynamics based solely on structural order is expected to contribute to the ultimate understanding of the long-standing glass-transition problem.

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Time-resolved thermal lens investigation of glassy dynamics in supercooled liquids: Theory and experiments

The Journal of Chemical Physics ◽

10.1063/5.0060310 ◽

2021 ◽

Vol 155 (7) ◽

pp. 074503

Author(s):

Pengfei Zhang ◽

Marco Gandolfi ◽

Francesco Banfi ◽

Christ Glorieux ◽

Liwang Liu

Keyword(s):

Thermal Lens ◽

Supercooled Liquids ◽

Glassy Dynamics ◽

Time Resolved ◽

Theory And Experiments

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Elemental mass loss in silicate minerals during x-ray analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177155 ◽

1990 ◽

Vol 48 (4) ◽

pp. 804-805

Author(s):

P.E. Champness ◽

R.W. Devenish

Keyword(s):

Mass Loss ◽

Current Density ◽

Damage Mechanism ◽

Beam Current ◽

Single Chain ◽

Plagioclase Feldspar ◽

X Ray ◽

Alkali Ions ◽

Structural Order ◽

Sheet Silicate

It has long been recognised that silicates can suffer extensive beam damage in electron-beam instruments. The predominant damage mechanism is radiolysis. For instance, damage in quartz, SiO2, results in loss of structural order without mass loss whereas feldspars (framework silicates containing Ca, Na, K) suffer loss of structural order with accompanying mass loss. In the latter case, the alkali ions, particularly Na, are found to migrate away from the area of the beam. The aim of the present study was to investigate the loss of various elements from the common silicate structures during electron irradiation at 100 kV over a range of current densities of 104 - 109 A m−2. (The current density is defined in terms of 50% of total current in the FWHM probe). The silicates so far ivestigated are:- olivine [(Mg, Fe)SiO4], a structure that has isolated Si-O tetrahedra, garnet [(Mg, Ca, Fe)3Al2Si3AO12 another silicate with isolated tetrahedra, pyroxene [-Ca(Mg, Fe)Si2O6 a single-chain silicate; mica [margarite, -Ca2Al4Si4Al4O2O(OH)4], a sheet silicate, and plagioclase feldspar [-NaCaAl3Si5O16]. Ion- thinned samples of each mineral were examined in a VG Microscopes UHV HB501 field- emission STEM. The beam current used was typically - 0.5 nA and the current density was varied by defocussing the electron probe. Energy-dispersive X-ray spectra were collected every 10 seconds for a total of 200 seconds using a Link Systems windowless detector. The thickness of the samples in the area of analysis was normally 50-150 nm.

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Faculty Opinions recommendation of Acyl chain length and saturation modulate interleaflet coupling in asymmetric bilayers: effects on dynamics and structural order.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717967691.793467359 ◽

2012 ◽

Author(s):

Jan Hoh

Keyword(s):

Chain Length ◽

Acyl Chain ◽

Structural Order ◽

Acyl Chain Length

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Signature of dynamical heterogeneity in spatial correlations of particle displacement and its temporal evolution in supercooled liquids

Physical Review Research ◽

10.1103/physrevresearch.2.022067 ◽

2020 ◽

Vol 2 (2) ◽

Cited By ~ 3

Author(s):

Indrajit Tah ◽

Smarajit Karmakar

Keyword(s):

Temporal Evolution ◽

Supercooled Liquids ◽

Particle Displacement ◽

Spatial Correlations ◽

Dynamical Heterogeneity

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Dynamical time scales of friction dynamics in active microrheology of a model glass

Soft Matter ◽

10.1039/d0sm02039g ◽

2021 ◽

Author(s):

Ata Madanchi ◽

Ji Woong Yu ◽

Mohamad Reza Rahimi Tabar ◽

Won Bo Lee ◽

S. E. E. Rahbari

Keyword(s):

Time Scales ◽

Supercooled Liquids ◽

Model Glass ◽

Heterogeneous Structures ◽

Dynamical Time ◽

Friction Dynamics

Owing to the local/heterogeneous structures in supercooled liquids, after several decades of research, it is now clear that supercooled liquids are structurally different from their conventional liquid counterparts. Accordingly, an...

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