期刊
JOURNAL OF PHYSICS-CONDENSED MATTER
卷 33, 期 6, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/1361-648X/abc4cc
关键词
Voronoi liquid; binary mixture; glass transition; molecular-dynamics simulations; mode-coupling theory
资金
- ANR LatexDry project of the French Agence Nationale de la Recherche [ANR-18-CE06-0001]
- Canada First Research Excellence Fund
- Quantum Materials and Future Technologies Program
- Dutch Research Council (NWO) through a START-UP grant
The study investigates the structural relaxation of a binary Voronoi mixture using molecular dynamics simulations and mode-coupling theory, finding no significant qualitative differences compared to similar analyses on simple liquids with pairwise interactions. The analysis suggests that it is possible to predict microscopic dynamic properties of the system based on static structural correlations, even though many-body interactions are involved.
The binary Voronoi mixture is a fluid model whose interactions are derived from the Voronoi-Laguerre tessellation of the configurations of the system. The resulting interactions are local and many-body. Here we perform molecular-dynamics (MD) simulations of an equimolar mixture that is weakly polydisperse and additive. For the first time we study the structural relaxation of this mixture in the supercooled-liquid regime. From the simulations we determine the time- and temperature-dependent coherent and incoherent scattering functions for a large range of wave vectors, as well as the mean-square displacements of both particle species. We perform a detailed analysis of the dynamics by comparing the MD results with the first-principles-based idealized mode-coupling theory (MCT). To this end, we employ two approaches: fits to the asymptotic predictions of the theory, and fit-parameter-free binary MCT calculations based on static-structure-factor input from the simulations. We find that many-body interactions of the Voronoi mixture do not lead to strong qualitative differences relative to similar analyses carried out for simple liquids with pair-wise interactions. For instance, the fits give an exponent parameter lambda approximate to 0.746 comparable to typical values found for simple liquids, the wavevector dependence of the Kohlrausch relaxation time is in good qualitative agreement with literature results for polydisperse hard spheres, and the MCT calculations based on static input overestimate the critical temperature, albeit only by a factor of about 1.2. This overestimation appears to be weak relative to other well-studied supercooled-liquid models such as the binary Kob-Andersen Lennard-Jones mixture. Overall, the agreement between MCT and simulation suggests that it is possible to predict several microscopic dynamic properties with qualitative, and in some cases near-quantitative, accuracy based solely on static two-point structural correlations, even though the system itself is inherently governed by many-body interactions.
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