论文标题

通过隐藏的潜在变量来解码铁电的域结构与功能之间的关系

Toward Decoding the Relationship between Domain Structure and Functionality in Ferroelectrics via Hidden Latent Variables

论文作者

Kalinin, Sergei V., Kelley, Kyle, Vasudevan, Rama K., Ziatdinov, Maxim

论文摘要

铁电材料中的极化开关机制从根本上与局部结构域结构和结构缺陷的存在联系起来,这些缺陷都可以充当成核和固定中心,并创建影响壁动力学的局部静电和机械去极化场。但是,域结构和极化动力学之间的一般相关机制仅被弱探索,从而排除了对相关物理机制的见解。在这里,使用卷积编码器码头网络探索了局部域结构与铁电材料中的切换行为之间的相关性,从而使图像可以通过编码潜在变量来使图像到频谱(IM2SPEC)和光谱(Spec2IM)翻译。后者反映了以下假设:域结构与极化切换之间的关系是简约的,即基于少量局部机制。对潜在变量分布及其实际空间表示的分析提供了对局部切换行为的可预测性的见解,因此提供了相关的物理机制。我们进一步提出,违反这些相关关系的区域,即降低了域结构的极化动态的可预测性,代表了详细研究的明显目标,例如在自动实验的背景下。这种方法提供了一个工作流程,以确定局部光谱响应与局部结构之间存在相关性,并且可以普遍应用于诸如PFM,扫描隧道显微镜(STM)和光谱学以及电子能量损失光谱光谱(EELS)等光谱成像技术中。

Polarization switching mechanisms in ferroelectric materials are fundamentally linked to local domain structure and presence of the structural defects, which both can act as nucleation and pinning centers and create local electrostatic and mechanical depolarization fields affecting wall dynamics. However, the general correlative mechanisms between domain structure and polarization dynamics are only weakly explored, precluding insight into the associated physical mechanisms. Here, the correlation between local domain structures and switching behavior in ferroelectric materials is explored using the convolutional encoder-decoder networks, enabling the image to spectral (im2spec) and spectral to image (spec2im) translations via encoding latent variables. The latter reflects the assumption that the relationship between domain structure and polarization switching is parsimonious, i.e. is based upon a small number of local mechanisms. The analysis of latent variables distributions and their real space representations provides insight into the predictability of the local switching behavior, and hence associated physical mechanisms. We further pose that the regions where these correlative relationships are violated, i.e. predictability of the polarization dynamics from domain structure is reduced, represent the obvious target for detailed studies, e.g. in the context of automated experiments. This approach provides a workflow to establish the presence of correlation between local spectral responses and local structure and can be universally applied to spectral imaging techniques such as PFM, scanning tunneling microscopy (STM) and spectroscopy, and electron energy loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM).

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