arXiv 2201.049702022-01cond-mat.mtrl-sci

从机器学习和因果关系深入了解双钙钛矿氧化物的阳离子排序

Insights into cation ordering of double perovskite oxides from machine learning and causal relations

Ayana Ghosh, Gayathri Palanichamy, Dennis P. Trujillo, Monirul Shaikh, Saurabh Ghosh

DOI：: 10.1021/acs.chemmater.2c00217

摘要：

这项工作使用第一原理理论计算结合机器学习（ML）和因果关系研究了双钙钛矿阳离子排序的起源。我们考虑了过渡金属离子族中A、A '、B和B'的各种氧化态，以构建不同的组成空间。采用传统ML分类算法（如随机森林（RF））的传统框架与适当的特征（包括几何驱动和关键结构模式）相结合，可以高度准确地预测A位点阳离子排序（约98%）。我们已经评估了ML模型的准确性，通过分析决策路径，分配概率置信区间，最后引入一个直接的非高斯非循环结构方程模型来研究因果关系。我们的研究表明，结构模式是划分层状，柱状和岩盐有序的最重要的特征。对于清晰的分层有序，A和A'之间的电荷差异是最重要的特征，这反过来又取决于B，B'电荷分离。基于ML模型的输出，我们设计了具有这些特征的函数形式，以导出形成清晰分层排序的能量差异。在朗道自由能膨胀中，倾斜、旋转和A位反铁电位移之间的三线性耦合成为A位阳离子有序形成的必要条件。

英文摘要：

This work investigates the origins of cation ordering of double perovskites using first-principles theory computations combined with machine learning (ML) and causal relations. We have considered various oxidation states of A, A', B, and B' from the family of transition metal ions to construct a diverse compositional space. A conventional framework employing traditional ML classification algorithms such as Random Forest (RF) coupled with appropriate features including geometry-driven and key structural modes leads to highly accurate prediction (~98%) of A-site cation ordering. We have evaluated the accuracy of ML models by entailing analyses of decision paths, assignments of probabilistic confidence bound, and finally introducing a direct non-Gaussian acyclic structural equation model to investigate causality. Our study suggests that the structural modes are the most important features for classifying layered, columnar and rock-salt ordering. For clear layered ordering, the charge difference between the A and A' is the most important feature which in turn depends on the B, B' charge separation. Based on the outputs from ML models, we have designed functional forms with these features to derive energy differences forming clear layered ordering. The trilinear coupling between tilt, rotation, and A-site antiferroelectric displacement in Landau free-energy expansion becomes the necessary condition behind the formation of A-site cation ordering.

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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