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arXiv 1306.2997cond-mat.mtrl-sci
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含汽相的相场晶体模型

Phase-Field Crystal Model with a Vapor Phase

Edwin J. Schwalbach, James A. Warren, Kuo-An Wu, Peter W. Voorhees

摘要:

相场晶体(PFC)模型能够解析材料在扩散时间尺度上的时间演化过程中的原子长度尺度特征。传统的PFC模型包含固相和液相,然而许多重要的材料加工现象也涉及气相。在这项工作中,我们添加了一个汽相到现有的PFC模型,并显示逼真的界面现象附近的三相点温度。例如,PFC模型在液体-蒸气界面处表现出密度振荡,这与实验和分子动力学模拟中的金属系统界面的可用数据相比是有利的。我们还量化的各向异性的固体-蒸汽表面能的二维PFC六方晶体,并找到定义良好的台阶能量从测量上的小面的接口。此外,应变场下的阶梯接口的特点和定性再现连续模型,模拟和实验数据的预测。最后,我们研究的动态情况下,一个晶体成过饱和汽相的阶梯流生长。这种广泛的表面和体缺陷模型的能力,使这个PFC模型的一个有用的工具,研究处理技术,如化学气相沉积或气-液-固生长的纳米线。

英文摘要:

Phase-Field Crystal (PFC) models are able to resolve atomic length scale features of materials during temporal evolution over diffusive time scales. Traditional PFC models contain solid and liquid phases, however many important materials processing phenomena involve a vapor phase as well. In this work, we add a vapor phase to an existing PFC model and show realistic interfacial phenomena near the triple point temperature. For example, the PFC model exhibits density oscillations at liquid-vapor interfaces that compare favorably to data available for interfaces in metallic systems from both experiment and molecular dynamics simulations. We also quantify the anisotropic solid-vapor surface energy for a 2D PFC hexagonal crystal and find well defined step energies from measurements on the faceted interfaces. Additionally, the strain field beneath a stepped interface is characterized and shown to qualitatively reproduce predictions from continuum models, simulations, and experimental data. Finally, we examine the dynamic case of step-flow growth of a crystal into a supersaturated vapor phase. The ability to model such a wide range of surface and bulk defects makes this PFC model a useful tool to study processing techniques such as Chemical Vapor Deposition or Vapor-Liquid-Solid growth of nanowires.

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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