Relaxation in a glassy binary mixture: Mode-coupling-like power laws, dynamic heterogeneity and a new non-Gaussian parameter

Abstract

We examine the relaxation of the Kob-Andersen Lennard-Jones binary mixture using Brownian dynamics computer simulations. We find that in accordance with mode-coupling theory the self-diffusion coefficient and the relaxation time show power-law dependence on temperature. However, different mode-coupling temperatures and power laws can be obtained from the simulation data depending on the range of temperatures chosen for the power-law fits. The temperature that is commonly reported as this system's mode-coupling transition temperature, in addition to being obtained from a power law fit, is a crossover temperature at which there is a change in the dynamics from the high temperature homogeneous, diffusive relaxation to a heterogeneous, hopping-like motion. The hopping-like motion is evident in the probability distributions of the logarithm of single-particle displacements: approaching the commonly reported mode-coupling temperature these distributions start exhibiting two peaks. Notably, the temperature at which the hopping-like motion appears for the smaller particles is slightly higher than that at which the hopping-like motion appears for the larger ones. We define and calculate a new non-Gaussian parameter whose maximum occurs approximately at the time at which the two peaks in the probability distribution of the logarithm of displacements are most evident.

Submitted for publication in Phys. Rev. E

References in corpus (12)

• Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture I: The van Hove Correlation Function
• Dynamical heterogeneities in a supercooled Lennard-Jones liquid
• String-like Clusters and Cooperative Motion in a Model Glass-Forming Liquid
• Scaling behavior in the $\beta$-relaxation regime of a supercooled Lennard-Jones mixture
• Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture II: Intermediate Scattering Function and Dynamic Susceptibility
• Spatial Correlations of Mobility and Immobility in a Glassforming Lennard-Jones Liquid
• How does the relaxation of a supercooled liquid depend on its microscopic dynamics?
• Real space origin of temperature crossovers in supercooled liquids
• Dynamical heterogeneities close to a colloidal gel
• Mean-Field Theory, Mode-Coupling Theory, and the Onset Temperature in Supercooled Liquids
• Independence of the relaxation of a supercooled fluid of its microscopic dynamics: need for yet another extension of the mode-coupling theory
• Lifetime of dynamic heterogeneities in a binary Lennard-Jones mixture

Cited by in corpus (38)

• Molecular dynamics simulations of glassy polymers
• Perspective: Nonequilibrium glassy dynamics in dense systems of active particles
• Relaxation in a glassy binary mixture: Comparison of the mode-coupling theory to a Brownian dynamics simulation
• The nonequilibrium glassy dynamics of self-propelled particles
• Structural relaxation of polydisperse hard spheres: comparison of the mode-coupling theory to a Langevin dynamics simulation
• Identifying time scales for violation/preservation of Stokes-Einstein relation in supercooled water
• Relaxation Scenarios in a Mixture of Large and Small Spheres: Dependence on the Size Disparity
• Cooperativity Beyond Caging: Generalized Mode Coupling Theory
• Analysis of a growing dynamic length scale in a glass-forming binary hard-sphere mixture
• Connections of activated hopping processes with the breakdown of the Stokes-Einstein relation and with aspects of dynamical heterogeneities
• Phase diagram of Kob-Andersen type binary Lennard-Jones mixtures
• Dynamics of particles and cages in an experimental 2D glass former
• Yield Stress Discontinuity in a Simple Glass
• Multi-time density correlation functions in glass-forming liquids: Probing dynamical heterogeneity and its lifetime
• Time scale for the onset of Fickian diffusion in supercooled liquids
• Tests of mode-coupling theory in two dimensions
• Numerical and Theoretical Study of a Monodisperse Hard-Sphere Glass Former
• Slow Dynamics of the High Density Gaussian Core Model
• Fickian crossover and lengthscales from two point functions in supercooled liquids
• Efficient Monte Carlo simulation of a glass forming binary mixture
• From caging to Rouse dynamics in polymer melts with intramolecular barriers: a critical test of the Mode Coupling Theory
• On mean-field theories of dynamics in supercooled liquids
• Tests of mode coupling theory in a simple model for two-component miscible polymer blends
• Mean-field dynamic criticality and geometric transition in the Gaussian core model
• Anisotropic spatially heterogeneous dynamics in a model glass-forming binary mixture
• NVU dynamics. II. Comparing to four other dynamics
• Classification of mobile- and immobile-molecule timescales for the Stokes-Einstein and Stokes-Einstein-Debye relations in supercooled water
• Effects of chain length on Rouse modes and non-Gaussianity in linear and ring polymer melts
• Efficient formulation of multitime generalized quantum master equations: Taming the cost of simulating 2D spectra
• Thermodynamics and its correlation with dynamics in a mean-field model and pinned systems: A comparative study using two different methods of entropy calculation
• Glassy dynamics of a binary Voronoi fluid: A mode-coupling analysis
• Single-file and normal diffusion of magnetic colloids in modulated channels
• Connecting microscopic simulations with kinetically constrained models of glasses
• Dynamical heterogeneities in an attraction driven colloidal glass
• A Comparative Study of a Class of Mean Field Theories of the Glass Transition
• Characterising the slow dynamics of the swap Monte Carlo algorithm
• Competing Relaxation Channels in Continuously Polydisperse Fluids: A Mode-Coupling Study
• The Geometric Mean Squared Displacement and the Stokes-Einstein Scaling in a Supercooled Liquid