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arXiv 1206.5154cond-mat.soft
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硬球晶体和晶体-流体界面的描述:密度泛函方法和相场晶体模型的临界比较

Description of hard sphere crystals and crystal-fluid interfaces: a critical comparison between density functional approaches and a phase field crystal model

M. Oettel, S. Dorosz, M. Berghoff, B. Nestler, T. Schilling

摘要:

在材料科学中,相场晶体方法已成为流行的结晶过程的模型。相场晶体模型本质上是Landau-Ginzburg型模型,它应该可以从所讨论的系统的基本微观描述中推导出来。我们提出了一个研究经典的密度泛函理论在三个阶段的近似导致一个特定的相场晶体模型,我们讨论了适用性的限制,从这些近似模型的结果。作为一个测试系统,我们选择了单分散硬球的三维悬浮液。我们讨论的密度泛函理论的水平是基本的测量理论,二阶泰勒展开,和最小相场晶体模型。我们计算了共存密度,空位浓度在晶相,界面张力和界面序参量配置文件,我们比较这些数量的模拟结果。本文还提出了一种拟合相场晶体模型自由参数的方法。

英文摘要:

In materials science the phase field crystal approach has become popular to model crystallization processes. Phase field crystal models are in essence Landau-Ginzburg-type models, which should be derivable from the underlying microscopic description of the system in question. We present a study on classical density functional theory in three stages of approximation leading to a specific phase field crystal model, and we discuss the limits of applicability of the models that result from these approximations. As a test system we have chosen the three--dimensional suspension of monodisperse hard spheres. The levels of density functional theory that we discuss are fundamental measure theory, a second-order Taylor expansion thereof, and a minimal phase-field crystal model. We have computed coexistence densities, vacancy concentrations in the crystalline phase, interfacial tensions and interfacial order parameter profiles, and we compare these quantities to simulation results. We also suggest a procedure to fit the free parameters of the phase field crystal model.

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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