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arXiv 0708.2979cond-mat.soft
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团簇晶体的相共存:超出吉布斯相律

Phase coexistence of cluster crystals: beyond the Gibbs phase rule

Bianca M. Mladek, Patrick Charbonneau, Daan Frenkel

摘要:

我们报告了一个研究的相位行为的多占据晶体通过模拟。我们认为,为了重现这种晶体的平衡行为,它是必不可少的处理作为一个约束的热力学变量的晶格位点的数量。由此产生的自由能计算,因此有很大的不同,从计划用于单占用晶格。使用我们的方法,我们得到的相图和体积模量的广义指数模型,形成集群晶体在高密度。我们将模拟结果与现有的理论预测进行比较。我们还确定了两种类型的密度波动,它们可能导致两种声音模式,并评估了相应的弹性常数。

英文摘要:

We report a study of the phase behavior of multiple-occupancy crystals through simulation. We argue that in order to reproduce the equilibrium behavior of such crystals it is essential to treat the number of lattice sites as a constraining thermodynamic variable. The resulting free-energy calculations thus differ considerably from schemes used for single-occupancy lattices. Using our approach, we obtain the phase diagram and the bulk modulus for a generalized exponential model that forms cluster crystals at high densities. We compare the simulation results with existing theoretical predictions. We also identify two types of density fluctuations that can lead to two sound modes and evaluate the corresponding elastic constants.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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