Anomalous diffusion and stretched exponentials in heterogeneous glass-forming liquids: Low-temperature behavior

Langer, J. S.; Mukhopadhyay, Swagatam

doi:10.1103/physreve.77.061505

Cited by 25 publications

(46 citation statements)

References 22 publications

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“…In a preceding paper [1], Mukhopadhyay and I studied a model of the diffusive motion of a tagged molecule in a heterogeneous glass-forming liquid. This model is based in part on the excitation-chain theory of the glass transition.…”

Section: Introductionmentioning

confidence: 99%

“…My purpose here is to reformulate [1] in a way that explores the decrease in the size of the heterogeneities as a function of increasing temperature above the glass transition. My ultimate goal is to understand the crossover between the thermally activated phenomena that occur near the glass temperature and the non-activated, fluidlike transport that is described at high temperatures by mode-coupling theory.…”

Section: Introductionmentioning

confidence: 99%

“…In this sense, the model has elements of kinetically constrained systems. [4,5,6,7,8,9,10] The analysis in [1] pertained only to behavior at temperatures T low enough that the heterogeneities are much larger than the molecular spacing. With that assumption, we found a clear decoupling between the slow α relaxation and the faster mobile motions that we identified as "β" cage-breaking rearrangements.…”

Section: Introductionmentioning

confidence: 99%

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mentioning

confidence: 99%

“…Here I extend this analysis to higher temperatures approaching the point where the heterogeneities disappear and thermal activation barriers become small. I start by modifying the continuous-time random-walk theory proposed in [1], and supplement this analysis with an extension of the excitation-chain theory of glass dynamics. I also use a key result from the shear-transformation-zone theory of viscous deformation of amorphous materials.…”

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Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior

Langer

2008

Phys. Rev. E

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In a preceding paper [1], Mukhopadhyay and I studied the diffusive motion of a tagged molecule in an heterogeneous glass-forming liquid at temperatures just above a glass transition. Among other features of this system, we postulated a relation between heterogeneity and stretched-exponential decay of correlations, and we also confirmed that systems of this kind generally exhibit non-Gaussian diffusion on intermediate length and time scales. Here I extend this analysis to higher temperatures approaching the point where the heterogeneities disappear and thermal activation barriers become small. I start by modifying the continuous-time random-walk theory proposed in [1], and supplement this analysis with an extension of the excitation-chain theory of glass dynamics. I also use a key result from the shear-transformation-zone theory of viscous deformation of amorphous materials. Elements of each of these theories are then used to interpret experimental data for ortho-terphenyl, specifially, the diffusion and viscosity coefficients and neutron scattering measurements of the self intermediate scattering function. Reconciling the theory with these data sets provides insights about the crossover between super-Arrhenius and Arrhenius dynamics, length scales of spatial heterogeneities, violation of the Stokes-Einstein relation in glass-forming liquids, and the origin of stretched exponential decay of correlations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior

Langer

2008

Phys. Rev. E

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Structural Dynamics in Thermal Treatment of Amorphous Indium Oxide Films

Ovadyahu

2019

Physica Status Solidi (b)

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Thermal treatment of amorphous indium oxide (InxO) films is used in various basic studies as a means of tuning the disorder perceived by the electronic system. In this process, the resistance of a given sample decreases, whereas its amorphous structure and chemical composition is preserved. The main effect of the process is an increase in the system density, which, in turn, leads to improved interatomic overlap manifested as improved conductivity. A similar effect has been observed in studies of other amorphous systems that were subjected to pressure. Herein, the Raman spectra of amorphous InxO change in response to thermal treatment in a similar way as in pressure experiments performed on other disordered and amorphous systems. A study of how thermal treatment changes the system dynamics is presented by monitoring the resistance versus time of InxO films following various stages of thermal treatment. The time dependence of the sample resistance fits the stretched exponential law with parameters that change systematically with repeated thermal treatment cycles. The implications of these results to slow dynamics phenomena that are governed by the Kohlrausch's law are discussed.

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