Anatomy of cage formation in a two-dimensional glass-forming liquid

Li, Bo; Lou, Kai; Kob, Walter; Granick, Steve

doi:10.1038/s41586-020-2869-5

Cited by 41 publications

(34 citation statements)

References 41 publications

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“…Indeed, the temperature-driven amorphous transformations in liquid H 2 O from the high to low density has been explained in these terms. The same has been argued for the glass transition in model systems [35][36][37] and seems also compatible with recent experimental observations [38]. The second one states that with pressure or temperature, the local coordination of materials built of polyhedra can evolve successively from low to high coordination through a series of percolation transitions.…”

Section: Discussionsupporting

confidence: 86%

Percolation transitions in compressed SiO2 glasses

Hasmy

Ispas

Hehlen

2021

Preprint

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Amorphous-amorphous transformations under pressure are generally explained by changes in the local structure from low to higher fold coordinated polyhedra [1-4]. However, as the notion of scale invariance at the critical thresholds has not been addressed, it is still unclear whether these transformations could be associated to true phase transitions. Here we report ab initio based calculations of compressed silica (SiO2) glasses showing that the structural changes from low- to high-density amorphous structures occur through a sequence of percolation transitions. When the pressure is increased up to 82 GPa, a series of long range ('infinite') percolating clusters built up by corner- or edge-shared tetrahedra, pentahedra, and eventually octahedra, emerge at some critical pressures and replace the previous phase of lower fold coordinated polyhedra and lower connectivity. This mechanism provides a natural explanation for the well-known mechanical anomaly around 3 GPa as well as for the structural irreversibility beyond 10 GPa, among others. Some of the amorphous structures that have been discovered mimic those of coesite IV and V crystals reported recently [5,6], highlighting the major role of SiO5 pentahedra-based polyamorphs in the densification process of vitreous silica. Our observations demonstrate that the percolation theory provides a robust framework to understand the nature and the pathway of the amorphous-amorphous transformations, and open a new avenue to predict unraveled amorphous solid phases and related liquids [7,8].

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Section: Discussionsupporting

confidence: 86%

Percolation transitions in compressed SiO2 glasses

Hasmy

Ispas

Hehlen

2021

Preprint

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“…It is evident that the relaxation dynamics slows down dramatically with decreasing value of IGD, represented by an extended plateau on the SISF curve, which corresponds to the secondary β-relaxation process. This trend indicates that motion of the low-IGD atoms is highly confined by the neighboring atoms, displaying a significant cage effect [67]. The revealed scenario for relaxation is consistent with that of diffusive MSD shown previously in Fig.…”

Section: Correlating Igd With the α-Relaxationsupporting

confidence: 90%

Machine-learning integrated glassy defect from an intricate configurational-thermodynamic-dynamic space

et al. 2021

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Optimizing materials' properties and functions by controlling defects in the crystalline phase has been a cornerstone of materials science and condensed matter physics. However, this paradigm has yet to be established in the broadly defined amorphous materials, which implies identification of very subtle structural features in an otherwise uniformly disordered medium. Here we propose and define a new integrated glassy defect (IGD), based on machine learning strategy informed by atomistic physics, and also by an extremely wide configurational, thermodynamic, and dynamic variables space of the disordered state. The IGD simultaneously includes positional topology and vibrational features, as well as the local morphology of the potential energy landscape. This unprecedented combination gives rise to a much more comprehensive and more effective definition of the "glassy defect", much beyond the conventional, purely structural input. IGD can be used not only as an efficient predictor of athermal plasticity, but is also transferable to detect both short-time vibrational anomalies (the boson peak), and long-time relaxation and diffusion dynamics in glasses. The integrated strategy is instrumental to build the long-sought structure-property relationship in complex media.

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“…However, the experiment [7] did not reveal a significant change in the passive orientational diffusion even at φ g , which suggests that lubrication-based dampening played a limited role. If friction is indeed present in experimental colloidal glass formers [7,31,36], this would limit their fundamental connection to idealized hard-sphere systems, but also offers new richness. This will be the subject of future study.…”

mentioning

confidence: 99%

Autonomously Probing Viscoelasticity in Disordered Suspensions

et al. 2020

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Recent experiments show a strong rotational diffusion enhancement for self-propelled microrheological probes in colloidal glasses. Here, we provide microscopic understanding using simulations with a frictional probe-medium coupling that converts active translation into rotation. Diffusive enhancement emerges from the medium's disordered structure and peaks at a second-order transition in the number of contacts. Our results reproduce the salient features of the colloidal glass experiment and support an effective description that is applicable to a broader class of viscoelastic suspensions.

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Anatomy of cage formation in a two-dimensional glass-forming liquid

Cited by 41 publications

References 41 publications

Percolation transitions in compressed SiO2 glasses

Percolation transitions in compressed SiO2 glasses

Machine-learning integrated glassy defect from an intricate configurational-thermodynamic-dynamic space

Autonomously Probing Viscoelasticity in Disordered Suspensions

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