论文标题

使用机器学习的原子模拟中晶体结构识别的以数据为中心的框架

A data-centric framework for crystal structure identification in atomistic simulations using machine learning

论文作者

Chung, Heejung, Freitas, Rodrigo, Cheon, Gowoon, Reed, Evan J.

论文摘要

在大尺度上进行的原子级建模可以研究具有原子分辨率的中尺度材料特性。这种跨尺度模拟的空间复杂性使它们不适合简单的人类视觉检查。取而代之的是,需要专门的结构表征技术来帮助解释。这些在历史上一直具有挑战性,需要大量的直觉和努力。在这里,我们为基本结构表征任务提出了一个替代框架:根据它们所属的晶体结构对原子进行分类。我们的方法是以数据为中心,有利于机器学习而不是启发式分类规则。一组数据科学工具和原子结构的简单本地描述符,以及有效的合成训练集。我们还介绍了第一个标准和公开可用的基准数据集,以评估算法用于晶体结构分类。证明我们以数据为中心的框架的表现优于所有最流行的启发式方法,尤其是在晶格最扭曲最扭曲的高温下,同时引入了对新晶体结构的系统性途径。此外,通过使用异常检测算法,我们的方法能够在无定形的原子基序(即非晶体阶段)和未知的晶体结构之间进行辨别,从而使其独特地适合探索性材料合成模拟。

Atomic-level modeling performed at large scales enables the investigation of mesoscale materials properties with atom-by-atom resolution. The spatial complexity of such cross-scale simulations renders them unsuitable for simple human visual inspection. Instead, specialized structure characterization techniques are required to aid interpretation. These have historically been challenging to construct, requiring significant intuition and effort. Here we propose an alternative framework for a fundamental structural characterization task: classifying atoms according to the crystal structure to which they belong. Our approach is data-centric and favors the employment of Machine Learning over heuristic rules of classification. A group of data-science tools and simple local descriptors of atomic structure are employed together with an efficient synthetic training set. We also introduce the first standard and publicly available benchmark data set for evaluation of algorithms for crystal-structure classification. It is demonstrated that our data-centric framework outperforms all of the most popular heuristic methods -- especially at high temperatures when lattices are the most distorted -- while introducing a systematic route for generalization to new crystal structures. Moreover, through the use of outlier detection algorithms our approach is capable of discerning between amorphous atomic motifs (i.e., noncrystalline phases) and unknown crystal structures, making it uniquely suited for exploratory materials synthesis simulations.

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