Scanning transmission electron microscopy (STEM) excels in accessing atomic-scale structure and chemistry. Enhancing our ability to directly image the functionalities of local features in materials has become one of the most important topics in the future development of STEM. Recently, differential phase contrast (DPC) imaging has been utilized to map the internal electric and magnetic fields in materials from nanoscale features such as p–n junctions, skyrmions, and even from individual atoms. Here, we use an ultra-low noise SCMOS detector in as the diffraction plane camera to collect four-dimensional (4D) datasets. The high angular resolution, efficient high-SNR acquisition, and modifiability of the camera allow it to function as a universal detector, where STEM imaging configurations, such as DPC, bright field, annular bright field, and annular dark field can all be reconstructed from a single 4D dataset. By examining a distorted perovskite, DyScO3, which possesses projected lattice spacings as small as 0.83 Å, we demonstrate DPC spatial resolution almost reaching the information limit of a 100 keV electron beam. In addition, the perovskite has ordered O-coordinations with alternating octahedral tilts, which can be quantitatively measured with single degree accuracy by taking advantage of DPC’s sensitivity to light atoms. The results, acquired on a standard Ronchigram camera as opposed to a specialized DPC detector, open up new opportunities to understand and design functional materials and devices that involve lattice and charge coupling at nano- and atomic-scales.

中文翻译：

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扫描透射电子显微镜中通用探测器的亚埃电场测量。

扫描透射电子显微镜 (STEM) 擅长观察原子尺度的结构和化学。提高我们直接成像材料局部特征功能的能力已成为STEM未来发展中最重要的课题之一。最近，微分相衬 (DPC) 成像已被用来绘制材料中纳米级特征（如 p-n 结、斯格明子）甚至单个原子的内部电场和磁场。在这里，我们使用超低噪声 SCMOS 探测器作为衍射平面相机来收集四维 (4D) 数据集。相机的高角分辨率、高效高信噪比采集和可修改性使其能够充当通用探测器，其中 DPC、明场、环形明场和环形暗场等 STEM 成像配置都可以从单个 4D 数据集。通过检查扭曲的钙钛矿 DyScO3（其投影晶格间距小至 0.83 Å），我们证明了 DPC 空间分辨率几乎达到 100 keV 电子束的信息极限。此外，钙钛矿具有交替八面体倾斜的有序O配位，利用DPC对轻原子的敏感性，可以以单度精度进行定量测量。这些结果是在标准 Ronchigram 相机而不是专用 DPC 探测器上获得的，为理解和设计涉及纳米和原子尺度晶格和电荷耦合的功能材料和设备提供了新的机会。