Probing the limits of the rigid-intensity-shift model in differential-phase-contrast scanning transmission electron microscopy
Probing the limits of the rigid-intensity-shift model in differential-phase-contrast scanning transmission electron microscopy
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DOI：
10.1103/physreva.97.043843
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发表时间：
2018-01
影响因子：
2.9
通讯作者：
L. Clark;H. Brown;D. Paganin;M. Morgan;T. Matsumoto;N. Shibata;T. Petersen;S. Findlay
中科院分区：
文献类型：
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作者：
L. Clark;H. Brown;D. Paganin;M. Morgan;T. Matsumoto;N. Shibata;T. Petersen;S. Findlay
微分相衬扫描透射电子显微镜（DPC-STEM）成像的刚性强度偏移模型假设由样品施加在探针上的相位梯度导致衍射图案强度刚性偏移与该相位梯度成比例的量。这种行为在实践中很少被准确地实现。通过结合实验结果，分析建模和数值计算，我们探讨了刚性强度位移行为的崩溃，以及这如何取决于相位梯度的大小和相位分布和探针尺寸中特征的相对尺度。我们提出的指导方针，当刚性强度偏移模型可以应用于定量相位重建使用分段检测器，并提出探针成形策略，以进一步提高精度。
The rigid-intensity-shift model of differential phase contrast scanning transmission electron microscopy (DPC-STEM) imaging assumes that the phase gradient imposed on the probe by the sample causes the diffraction pattern intensity to shift rigidly by an amount proportional to that phase gradient. This behaviour is seldom realised exactly in practice. Through a combination of experimental results, analytical modelling and numerical calculations, we explore the breakdown of the rigid-intensity-shift behaviour and how this depends on the magnitude of the phase gradient and the relative scale of features in the phase profile and the probe size. We present guidelines as to when the rigid-intensity-shift model can be applied for quantitative phase reconstruction using segmented detectors, and propose probe-shaping strategies to further improve the accuracy.