The Effect of Dynamical Scattering on Single-plane Phase Retrieval in Electron Ptychography
The Effect of Dynamical Scattering on Single-plane Phase Retrieval in Electron Ptychography
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DOI：
10.1093/micmic/ozac022
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发表时间：
2022-12
影响因子：
2.8
通讯作者：
Laura Clark;G. Martinez;C. O’Leary;Hao Yang;Zhiyuan Ding;T. Petersen;S. Findlay;P. Nellist
中科院分区：
文献类型：
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作者：
Laura Clark;G. Martinez;C. O’Leary;Hao Yang;Zhiyuan Ding;T. Petersen;S. Findlay;P. Nellist
扫描电子显微镜上的分段和像素化探测器使复杂的样品传输函数得以重建。成像传输函数是解释样品的电磁特性的关键，因此，四维扫描透射式电子显微镜(4D-STEM)成像技术对于我们理解功能材料至关重要。许多用于重建传输函数的算法依赖于乘法近似和(弱)位相物体近似，这对于许多材料是无效的，特别是在高分辨率下。在这里，我们研究了简单相位成像在较厚的样品中的故障。我们展示了在模拟GaN 4D-STEM数据集的厚度序列上集成的质心成像、单边带层析和Wigner分布反卷积的行为。我们还给出了使用这些算法获得更可解释的数据集的最佳聚焦条件的指导。
Segmented and pixelated detectors on scanning transmission electron microscopes enable the complex specimen transmission function to be reconstructed. Imaging the transmission function is key to interpreting the electric and magnetic properties of the specimen, and as such four-dimensional scanning transmission electron microscopy (4D-STEM) imaging techniques are crucial for our understanding of functional materials. Many of the algorithms used in the reconstruction of the transmission function rely on the multiplicative approximation and the (weak) phase object approximation, which are not valid for many materials, particularly at high resolution. Herein, we study the breakdown of simple phase imaging in thicker samples. We demonstrate the behavior of integrated center of mass imaging, single-side band ptychography, and Wigner distribution deconvolution over a thickness series of simulated GaN 4D-STEM datasets. We further give guidance as to the optimal focal conditions for obtaining a more interpretable dataset using these algorithms.