发表机构
University of Tennessee; Oak Ridge National Laboratory; National Academy of Sciences of Ukraine; Frantsevich Institute for Problems of Materials Science; University of Maryland（田纳西大学; 橡树岭国家实验室; 乌克兰国家科学院; 弗兰采维奇材料科学问题研究所; 马里兰大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究开发潜场重构框架，结合原子分辨STEM数据，揭示Sm掺杂BiFeO3随Sm含量变化的铁电相向非极性Pnma相的成分驱动相演化规律，为铁性材料相演化解析提供新方法。
AI 中文摘要
铁电材料的功能由极化、应变、晶格旋转和结构有序性的空间组织与耦合决定，这些信息可通过原子分辨扫描透射电子显微镜（STEM）图像获取。传统上，原子分辨STEM数据的定量解释依赖于定位原子列并将其拟合坐标转换为局部结构描述符。本研究开发了一种基于场的方法，将原子分辨图像表示为空间变化的潜布拉格场，其振幅和相位提供了晶体有序性、晶格位移、应变、旋转及模式特异性残余结构的连续映射，可从潜场解码观测到的原子分辨图像。将该框架应用于Sm取代BiFeO3的图像系列，涵盖Sm含量0-20%，跨越R3c铁电相与正交非极性Pnma相之间的成分驱动边界。以传统原子分辨参数化作为独立验证，结果显示重构的布拉格振幅追踪局部原子列强度，场衍生的剪切再现了原子拟合得到的单胞角畸变。综合分析揭示了系统演化过程：低Sm浓度下为延伸铁电畴，中间成分时出现并生长具有周期加倍Pnma有序性的局域区域，高Sm含量时转变为连通的Pnma主导状态；周期加倍有序性伴随增强的剪切和晶格旋转，以及铁电畴结构的逐步重组。这些结果确立了潜场重构作为原子定位的物理解释性补充，为解析铁性材料中成分驱动的相演化提供了统一框架。
英文摘要
Functionalities of ferroelectric materials are governed by the spatial organization and coupling of polarization, strain, lattice rotation, and structural order accessible via atomically resolved scanning transmission electron microscopy (STEM) images. Quantitative interpretation of atomic-resolution STEM data has conventionally relied on locating atomic columns and converting their fitted coordinates into local structural descriptors. Here, we develop a field-based approach in which atomic-resolution images are represented by spatially varying latent Bragg fields, whose amplitudes and phases provide continuous maps of crystalline order, lattice displacement, strain, rotation, and mode-specific residual structure. The observed atomically resolved images are decoded from the latent fields. We apply this framework to image series of Sm-substituted BiFeO3 spanning 0-20% Sm and crossing the composition-driven boundary between the R3c ferroelectric phase and the orthorhombic, nonpolar Pnma phase. Conventional atom-resolved parameterization is used as an independent validation, showing that reconstructed Bragg amplitude tracks local atomic-column intensity and that field-derived shear reproduces unit-cell angular distortions obtained from atom fitting. The combined analysis reveals a systematic evolution from extended ferroelectric domains at low Sm concentration, through the appearance and growth of localized regions with period-doubled Pnma order at intermediate compositions, to a connected Pnma-dominated state at high Sm content. The period-doubled order is accompanied by enhanced shear and lattice rotation and by progressive reorganization of the ferroelectric domain structure. These results establish latent-field reconstruction as a physically interpretable complement to atom finding and provide a unified framework for resolving composition-driven phase evolution in ferroic materials.
