Dynamics and energy landscape in a tetrahedral network glass-former: Direct comparison with models of fragile liquids

Abstract

We report Molecular Dynamics simulations for a new model of tetrahedral network glass-former, based on short-range, spherical potentials. Despite the simplicity of the forcefield employed, our model reproduces some essential physical properties of silica, an archetypal network-forming material. Structural and dynamical properties, including dynamic heterogeneities and the nature of local rearrangements, are investigated in detail and a direct comparison with models of close-packed, fragile glass-formers is performed. The outcome of this comparison is rationalized in terms of the properties of the Potential Energy Surface, focusing on the unstable modes of the stationary points. Our results indicate that the weak degree of dynamic heterogeneity observed in network glass-formers may be attributed to an excess of localized unstable modes, associated to elementary dynamical events such as bond breaking and reformation. On the contrary, the more fragile Lennard-Jones mixtures are characterized by a larger fraction of extended unstable modes, which lead to a more cooperative and heterogeneous dynamics.

26 pages, 18 figures, added links to animations, corrected typos in sec. 2

References in corpus (35)

• Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture I: The van Hove Correlation Function
• Cooling rate effects in amorphous Silica: A Computer Simulation Study
• Irreversible reorganization in a supercooled liquid originates from localised soft modes
• Static and Dynamic Properties of a Viscous Silica Melt Molecular Dynamics Computer Simulations
• Fragile-to-strong transition and polyamorphism in the energy landscape of liquid silica
• Coarse-grained microscopic model of glass formers
• Spontaneous and induced dynamic fluctuations in glass-formers I: General results and dependence on ensemble and dynamics
• Computer simulations of liquid silica: equation of state and liquid-liquid phase transition
• Understanding fragility in supercooled Lennard-Jones mixtures. I. Locally preferred structures
• Some Finite Size Effects in Simulations of Glass Dynamics
• Spontaneous and induced dynamic correlations in glass-formers II: Model calculations and comparison to numerical simulations
• Democratic particle motion for meta-basin transitions in simple glass-formers
• Geometric approach to the dynamic glass transition
• Structure and dynamics in glass-formers: predictability at large length scales
• The relaxation dynamics of a viscous silica melt: II The intermediate scattering functions
• Heterogeneous Dynamics, Marginal Stability and Soft Modes in Hard Sphere Glasses
• Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study
• Temperature dependence of spatially heterogeneous dynamics in a model of viscous silica
• Phase diagram of silica from computer simulation
• Fragile vs strong liquids: a saddles ruled scenario
• The Origin of the Fragile-to-Strong Crossover in Liquid Silica as Expressed by its Potential Energy Landscape
• Stability of supercooled binary liquid mixtures
• Crystallization of the Kob-Andersen binary Lennard-Jones liquid
• On the relationship between structure and dynamics in a supercooled liquid
• Quasi-saddles as relevant points of the potential energy surface in the dynamics of supercooled liquids
• Revisiting the slow dynamics of a silica melt using Monte Carlo simulations
• Configuration space connectivity across the fragile to strong transition in silica
• General features of the energy landscape in Lennard-Jones like model liquids
• The vibrational dynamics of vitreous silica: Classical force fields vs. first-principles
• Slow dynamics in a primitive tetrahedral network model
• Understanding fragility in supercooled Lennard-Jones mixtures. II. Potential energy surface
• Computer investigation of the energy landscape of amorphous silica
• Are there localized saddles behind the heterogeneous dynamics of supercooled liquids?
• A spherical model with directional interactions: I. Static properties
• Fragile-strong transitions and polyamorphism in glass former fluids

Cited by in corpus (21)

• Persistent Homology Analysis for Materials Research and Persistent Homology Software: HomCloud
• Perspective: Configurational entropy of glass-forming liquids
• Relaxation and physical aging in network glasses: a review
• Correlation between Fragility and the Arrhenius Crossover Phenomenon in Metallic, Molecular, and Network Liquids
• Finite size effects in the dynamics of glass-forming liquids
• Multiple length and time scales of dynamic heterogeneities in model glass-forming liquids: A systematic analysis of multi-point and multi-time correlations
• Strong geometric frustration in model glassformers
• Non-Equilibrium Phase Transition in an Atomistic Glassformer: the Connection to Thermodynamics
• Static triplet correlations in glass-forming liquids: A molecular dynamics study
• A localization transition underlies the mode-coupling crossover of glasses
• Elementary plastic events in amorphous silica
• Dimensionality reduction of local structure in glassy binary mixtures
• Determination of onset temperature from the entropy for fragile to strong liquids
• The role of pair correlation function in the dynamical transition predicted by the mode coupling theory
• Mean-field dynamic criticality and geometric transition in the Gaussian core model
• Tuning Pairwise Potential Can Control the Fragility of Glass-Forming Liquids: From Tetrahedral Network to Isotropic Soft Sphere Models
• Composition dependence of the glass forming ability in binary mixtures: The role of demixing entropy
• Avalanches and Structural Change in Cyclically Sheared Silica Glass
• Reduced strength and extent of dynamic heterogeneity in a strong glass former as compared to fragile glass formers
• Growing length scale accompanying the vitrification: A perspective based on non-singular density fluctuations
• Glassy dynamics and crystalline local order in two-dimensional amorphous silica