Dynamic and thermodynamic crossover scenarios in the Kob-Andersen mixture: Insights from multi-CPU and multi-GPU simulations

Abstract

The physical behavior of glass-forming liquids presents complex features of both dynamic and thermodynamic nature. Some studies indicate the presence of thermodynamic anomalies and of crossovers in the dynamic properties, but their origin and degree of universality is difficult to assess. Moreover, conventional simulations are barely able to cover the range of temperatures at which these crossovers usually occur. To address these issues, we simulate the Kob-Andersen Lennard-Jones mixture using efficient protocols based on multi-CPU and multi-GPU parallel tempering. Our setup enables us to probe the thermodynamics and dynamics of the liquid at equilibrium well below the critical temperature of mode-coupling theory, $T_{\mathrm{MCT}}=0.435$. We find that below $T=0.4$ the analysis is hampered by partial crystallization of the metastable liquid, which nucleates extended regions populated by large particles arranged in an fcc structure. By filtering out crystalline samples, we reveal that the specific heat grows in a regular manner down to $T=0.38$. Possible thermodynamic anomalies suggested by previous studies can thus occur only in a region of the phase diagram where the system is highly metastable. Using the equilibrium configurations obtained from the parallel tempering simulations, we perform molecular dynamics and Monte Carlo simulations to probe the equilibrium dynamics down to $T=0.4$. A temperature-derivative analysis of the relaxation time and diffusion data allows us to assess different dynamic scenarios around $T_{\mathrm{MCT}}$. Hints of a dynamic crossover come from analysis of the four-point dynamic susceptibility. Finally, we discuss possible future numerical strategies to clarify the nature of crossover phenomena in glass-forming liquids.

12 pages, 9 figures, contribution to the special issue "Advances in Computational Methods for Soft Matter Systems". Data relevant to this work are available at https://doi.org/10.5281/zenodo.1227830

References in corpus (12)

• Theoretical perspective on the glass transition and amorphous materials
• Growing length and time scales in glass forming liquids
• Spontaneous and induced dynamic fluctuations in glass-formers I: General results and dependence on ensemble and dynamics
• Spontaneous and induced dynamic correlations in glass-formers II: Model calculations and comparison to numerical simulations
• Locally preferred structures and many-body static correlations in viscous liquids
• Finite size effects in the dynamics of glass-forming liquids
• Strong geometric frustration in model glassformers
• Non-linear dynamic response of glass-forming liquids to random pinning
• Crystallisation Instability in Glassforming Mixtures
• Equilibrium equation of state of a hard sphere binary mixture at very large densities using replica exchange Monte-Carlo simulations
• Frequency dependence of specific heat in supercooled liquid water and emergence of correlated dynamics
• On the nature of the glass transition in atomistic models of glass formers

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