Energy Landscape, Antiplasticization, and Polydispersity Induced Crossover of Heterogeneity in Supercooled Polydisperse Liquids

Abraham, Sneha Elizabeth; Bhattacharrya, Sarika Maitra; Bagchi, Biman

doi:10.1103/physrevlett.100.167801

Cited by 48 publications

(59 citation statements)

References 41 publications

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“…4 We thus find no support for a direct relation between the extent of cooperative motion L and a variation of the stretching exponent β s . We note that molecular dynamics simulations of model GF liquids have indicated an appreciable T dependence of β s 132 and it might be worthwhile in the future to examine how β s varies in relation to L and α. The present observations make it clear, however, that no universal relation exists between β s and the extent of collective motion L in the interfacial dynamics of our NPs.…”

Section: Model Relating Mobility Fluctuations To the Scale Of Collectmentioning

confidence: 91%

Glassy interfacial dynamics of Ni nanoparticles: part I Colored noise, dynamic heterogeneity and collective atomic motion

Zhang

Douglas

2013

Soft Matter

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Most condensed materials exhibit a significant fraction of atoms, molecules or particles that are strongly interacting with each other, while being configured geometrically at any instant of time in an ‘amorphous’ state having a relatively uniform density. Recently, both simulations and experiments have revealed that the dynamics of diverse condensed amorphous materials is generally characterized by significant heterogeneity in the local mobility and by progressively increasing collective motion upon cooling that takes the form of string-like collective particle rearrangements. The direct experimental observation of this type of collective motion, which has been directly linked to the growing relaxation times of glass-forming materials, and its quantification under different thermodynamic conditions, has so far been restricted to colloidal and driven granular fluids. The present work addresses the fundamental problem of how to determine the scale of this type of collective motion in materials composed of molecules or atoms. The basic premise of our work is that large scale dynamic particle clustering in amorphous materials must give rise to large fluctuations in particle mobility so that transport properties, especially those related to particle mobility, should naturally exhibit noise related to the cooperative motion scale. In our initial exploratory study seeking a relationship of this kind, we find 1/fα or ‘colored noise’, in both potential energy and particle displacements fluctuations of the atoms within the glassy interfacial layer of Ni nanoparticles (NPs). A direct relation between the particle displacement (mobility) noise exponent α and the average polymerization index of the string-like collective motion L is observed for a range of NP sizes, temperatures and for surface doping of the NPs with other metal atoms (Ag, Au, Pt) to change of fragility of the glassy interfacial layer at the surface of the Ni NPs. We also introduce a successful analytic model to understand this relationship between α and L

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Section: Model Relating Mobility Fluctuations To the Scale Of Collectmentioning

confidence: 91%

Glassy interfacial dynamics of Ni nanoparticles: part I Colored noise, dynamic heterogeneity and collective atomic motion

Zhang

Douglas

2013

Soft Matter

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“…The micro-scopic origin of fragility has been investigated in many numerical studies [13][14][15][16][17]. In these studies, attempts were made to tune the fragility by changing different parameters of the system, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…In these studies, attempts were made to tune the fragility by changing different parameters of the system, e.g. the degree of polydispersity in particle size [13], softness of the pair potential [16], the density of a system of particles interacting via a Hertzian potential [15], the composition of binary glass-forming liquids [14], and the height of a narrow repulsive spike in the pair potential [17]. In some of these cases [13,16], the fragility was found to depend weakly on the tuning parameters, so that no clear conclusion about the origin of fragility could be reached.…”

Section: Introductionmentioning

confidence: 99%

Understanding the dynamics of glass-forming liquids with random pinning within the random first order transition theory

Chakrabarty

Das

Karmakar

et al. 2016

The Journal of Chemical Physics

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Extensive computer simulations are performed for a few model glass-forming liquids in both two and three dimensions to study their dynamics when a randomly chosen fraction of particles are frozen in their equilibrium positions. For all the studied systems, we find that the temperaturedependence of the α relaxation time extracted from an overlap function related to the self part of the density autocorrelation function can be explained within the framework of the Random First Order Transition (RFOT) theory of the glass transition. We propose a scaling description to rationalize the simulation results and show that our data for the α relaxation time for all temperatures and pin concentrations are consistent with this description. We find that the fragility parameter obtained from fits of the temperature dependence of the α relaxation time to the Vogel-Fulcher-Tammann (VFT) form decreases by almost an order of magnitude as the pin concentration is increased from zero. Our scaling description relates the fragility parameter to the static length scale of RFOT and thus provides a physical understanding of fragility within the framework of the RFOT theory. Implications of these findings for the values of the exponents appearing in the RFOT theory are discussed.

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“…Despite considerable research effort, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and the observation of many empirical correlations between fragility and other material properties, a fully satisfactory understanding of fragility has not yet been reached. Such understanding has been sought, broadly, along two lines.…”

Section: Introductionmentioning

confidence: 99%

Dependence of the fragility of a glass former on the softness of interparticle interactions

Sengupta

Vasconcelos

Affouard

et al. 2011

The Journal of Chemical Physics

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We study the influence of the softness of the interparticle interactions on the fragility of a glass former by considering three model binary mixture glass formers. The interaction potential between particles is a modified Lennard-Jones type potential, with the repulsive part of the potential varying with an inverse power q of the interparticle distance, and the attractive part varying with an inverse power p. We consider the combinations (12,11) (model I), (12,6) (model II), and (8,5) (model III) for (q,p) such that the interaction potential becomes softer from model I to III. We evaluate the kinetic fragilities from the temperature variation of diffusion coefficients and relaxation times, and a thermodynamic fragility from the temperature variation of the configurational entropy. We find that the kinetic fragility increases with increasing softness of the potential, consistent with previous results for these model systems, but at variance with the thermodynamic fragility, which decreases with increasing softness of the interactions, as well as expectations from earlier results. We rationalize our results by considering the full form of the Adam-Gibbs relation, which requires, in addition to the temperature dependence of the configurational entropy, knowledge of the high temperature activation energies in order to determine fragility. We show that consideration of the scaling of the high temperature activation energy with the liquid density, analyzed in recent studies, provides a partial rationalization of the observed behavior.

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Energy Landscape, Antiplasticization, and Polydispersity Induced Crossover of Heterogeneity in Supercooled Polydisperse Liquids

Cited by 48 publications

References 41 publications

Glassy interfacial dynamics of Ni nanoparticles: part I Colored noise, dynamic heterogeneity and collective atomic motion

Glassy interfacial dynamics of Ni nanoparticles: part I Colored noise, dynamic heterogeneity and collective atomic motion

Understanding the dynamics of glass-forming liquids with random pinning within the random first order transition theory

Dependence of the fragility of a glass former on the softness of interparticle interactions

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