Topology of covalent non-crystalline solids I: Short-range order in chalcogenide alloys

Phillips, J. C.

doi:10.1016/0022-3093(79)90033-4

Cited by 1,847 publications

(1,112 citation statements)

References 32 publications

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“…For the homogeneous case, the bulk modulus depended mainly on the mean atomic coordination, with a Spearman's rank correlation coefficient [35] ρ = 0.98 -supporting previous studies also pointing out this trend [12,[16][17][18]. For heterogeneous networks, the dependence on the mean correlation diminished a little, with ρ = 0.9.…”

Section: Resultssupporting

confidence: 76%

Modeling of amorphous carbon structures with arbitrary structural constraints

Jornada¹,

Gava²,

Martinotto³

et al. 2010

J. Phys.: Condens. Matter

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In this paper we describe a method to generate amorphous structures with arbitrary structural constraints. This method employs the Simulated Annealing algorithm to minimize a simple yet carefully tailored Cost Function (CF). The Cost Function is composed of two parts: a simple harmonic approximation for the energy-related terms and a cost that penalizes configurations that do not have atoms in the desired coordinations. Using this approach, we generated a set of amorphous carbon structures spawning nearly all the possible combinations of sp, sp 2 and sp 3 hybridizations. The bulk moduli of this set of amorphous carbons structures was calculated using Brenner's potential. The bulk modulus strongly depends on the mean coordination, following a power law behavior with an exponent ν = 1.51 ± 0.17. A modified Cost Function that segregates carbon with different hybridizations is also presented, and another set of structures was generated.With this new set of amorphous materials, the correlation between the bulk modulus and the mean coordination weakens. This method proposed can be easily modified to explore the effects on physical properties of the presence hydrogen, dangling bonds, and structural features such as carbon rings.

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Section: Resultssupporting

confidence: 76%

Modeling of amorphous carbon structures with arbitrary structural constraints

Jornada¹,

Gava²,

Martinotto³

et al. 2010

J. Phys.: Condens. Matter

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“…This is directly inspired by the classical mechanics view of topological constraints associating large/small radial or angular motion with the absence/ presence of corresponding bond-stretching (BS) and bondbending (BB) restoring forces 15,16 . By building on the concept of Maxwell rigidity 5,6 , earlier work on amorphous networks 17,18 has shown that such BS constraints can actually be simply enumerated from the coordination number r i of the atoms, leading to a contributions of r i /2 for the BS constraint, each bond/ interaction being shared by two neighbours. Given the increase of the Si and O coordination with pressure ( Fig.…”

Section: Glass Transition Cyclementioning

confidence: 99%

Densified network glasses and liquids with thermodynamically reversible and structurally adaptive behaviour

2015

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If crystallization can be avoided during cooling, a liquid will display a substantial increase of its viscosity, and will form a glass that behaves as a solid with a relaxation time that grows exponentially with decreasing temperature. Given this 'off-equilibrium' nature, a hysteresis loop appears when a cooling/heating cycle is performed across the glass transition. Here we report on molecular dynamics simulations of densified glass-forming liquids that follow this kind of cycle. Over a finite pressure interval, minuscule thermal changes are found, revealing glasses of 'thermally reversible' character with optimal volumetric or enthalpic recovery. By analysing the topology of the atomic network structure, we find that corresponding liquids adapt under the pressure-induced increasing stress by experiencing larger bond-angle excursions. The analysis of the dynamic behaviour reveals that the structural relaxation time is substantially reduced in these adaptive liquids, and also drives the reversible character of the glass transition. Ultimately, the results substantiate the notion of stress-free (Maxwell isostatic) rigidity in disordered molecular systems, while also revealing new implications for the topological engineering of complex materials.

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“…Instead of density and shear stress, Phillips argued that the key control variable is the glass composition [2]. Based on a model of rigidity percolation proposed by Thorpe, where springs are randomly deposited on a lattice [3,4], it was argued that glass properties are controlled by a critical point at zero temperature.…”

Section: Introductionmentioning

confidence: 99%

The jamming scenario—an introduction and outlook

Liu

Nagel

Saarloos

et al. 2011

Dynamical Heterogeneities in Glasses, Colloids, and Granular Media

119

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Abstract. The jamming scenario of disordered media, formulated about 10 years ago, has in recent years been advanced by analyzing model systems of granular media. This has led to various new concepts that are increasingly being explored in in a variety of systems. This chapter contains an introductory review of these recent developments and provides an outlook on their applicability to different physical systems and on future directions. The first part of the paper is devoted to an overview of the findings for model systems of frictionless spheres, focussing on the excess of low-frequency modes as the jamming point is approached. Particular attention is paid to a discussion of the cross-over frequency and length scales that govern this approach. We then discuss the effects of particle asphericity and static friction, the applicability to bubble models for wet foams in which the friction is dynamic, the dynamical arrest in colloids, and the implications for molecular glasses.

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Topology of covalent non-crystalline solids I: Short-range order in chalcogenide alloys

Cited by 1,847 publications

References 32 publications

Modeling of amorphous carbon structures with arbitrary structural constraints

Modeling of amorphous carbon structures with arbitrary structural constraints

Densified network glasses and liquids with thermodynamically reversible and structurally adaptive behaviour

The jamming scenario—an introduction and outlook

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