In this work, molecular dynamics (MD) simulations of ferroelectric BaTiO3 are used to generate parameters for a phase-field (PF) model. The MD simulations provide important input parameters, such as elastic and piezoelectric properties, as well as domain wall (DW) widths and velocities. A parameterization technique is proposed to incorporate the MD results into the PF simulations, allowing for the generation of relevant parameters. Anisotropic interface energy coefficients are used to match the widths of both the 180° and 90° DWs in the PF simulations to the MD data. The velocities of the DWs are calculated and compared to the results obtained from MD simulations, demonstrating excellent agreement. Furthermore, we investigate the disparity between coercive fields obtained from PF simulations and MD simulations. Initially, our PF simulations yield coercive fields approximately twice as high as those observed in MD simulations. To address this discrepancy, we introduce a nucleus into the PF simulation system. The parameters of this nucleus are derived from a statistical analysis of coercive field data from MD simulations. By incorporating the nucleus model, we achieve a coercive field in PF simulations that closely aligns with the MD results. Validation of the parameterized PF model using MD data obtained with different initial conditions and thermodynamic constraints shows good agreement, further confirming the model’s accuracy.

中文翻译：

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根据分子动力学数据对铁电体的相场模型进行参数化


在这项工作中，铁电 BaTiO3 的分子动力学 （MD） 模拟用于生成相场 （PF） 模型的参数。MD 仿真提供了重要的输入参数，例如弹性和压电属性，以及畴壁 （DW） 宽度和速度。提出了一种参数化技术，将 MD 结果纳入 PF 模拟，从而允许生成相关参数。各向异性界面能量系数用于将 PF 仿真中 180° 和 90° DW 的宽度与 MD 数据相匹配。计算 DW 的速度并将其与 MD 模拟获得的结果进行比较，显示出极好的一致性。此外，我们研究了从 PF 模拟和 MD 模拟获得的矫顽力场之间的差异。最初，我们的 PF 模拟产生的矫顽力场大约是 MD 模拟中观察到的矫顽力场的两倍。为了解决这一差异，我们在 PF 仿真系统中引入了一个原子核。该核的参数来自 MD 模拟的矫顽场数据的统计分析。通过结合核模型，我们在 PF 模拟中实现了与 MD 结果紧密一致的矫顽力场。使用在不同初始条件和热力学约束下获得的 MD 数据对参数化 PF 模型的验证显示出良好的一致性，进一步证实了模型的准确性。