arXiv 2512.194602025-12-23physics.opticscond-mat.mtrl-sciphysics.comp-ph

通过融合互补的散射通道实现4D-STEM中的无间隙信息传输

Gap-free Information Transfer in 4D-STEM via Fusion of Complementary Scattering Channels

Shengbo You, Georgios Varnavides, Sagar Khavnekar, Nikita Palatkin, Sihan Shao, Mingjian Wu, Daniel Stroppa, Darya Chernikova, Baixu Zhu, Ricardo Egoavil, Stefa… 展开作者

Shengbo You, Georgios Varnavides, Sagar Khavnekar, Nikita Palatkin, Sihan Shao, Mingjian Wu, Daniel Stroppa, Darya Chernikova, Baixu Zhu, Ricardo Egoavil, Stefano Vespucci, Xingchen Ye, Florian K. M. Schur, Erdmann Spiecker, Philipp Pelz

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AI总结：

本文提出融合互补散射通道的FF-STEM技术，通过结合ptychographic相位重建与暗场成像，实现无间隙信息传输，提升4D-STEM成像的对比度和定量精度。

摘要：

线性相位对比扫描透射电子显微镜（STEM）技术广泛用于高通量4D-STEM采集，以增强弱散射和束敏感材料的相位对比。在这些模式中，低空间频率的对比转移通常被抑制，导致具有特征对比间隙的限制性定量成像。保留低频相位对比的方法存在，但通常需要显著增加实验复杂性，限制了常规使用。暗场STEM成像通过捕获散射出亮场盘的电子来获取缺失的低频信息，但丢弃了大量散射信号，因此剂量效率低。引入了融合全场STEM（FF-STEM）作为4D-STEM成像模式，通过在单次采集中结合ptychographic相位重建与校正倾斜的暗场成像，克服了这一限制。亮场数据用于估计探针像差并重建高分辨率相位图像，而暗场数据提供互补的低频对比。两个通道通过傅里叶空间中的最小方差加权（基于频谱信噪比）进行最佳融合，从而产生无间隙、高对比和定量忠实的图像。FF-STEM保留了ptychography的上采样和深度分层能力，添加了暗场成像特有的稳健低频对比，并实现了高效、近实时的重建。

英文摘要：

Linear phase-contrast scanning transmission electron microscopy (STEM) techniques compatible with high-throughput 4D-STEM acquisition are widely used to enhance phase contrast in weakly scattering and beam-sensitive materials. In these modalities, contrast transfer is often suppressed at low spatial frequencies, resulting in a characteristic contrast gap that limits quantitative imaging. Approaches that retain low-frequency phase contrast exist but typically require substantially increased experimental complexity, restricting routine use. Dark-field STEM imaging captures this missing low-frequency information through electrons scattered outside the bright-field disk, but discards a large fraction of the scattered signal and is therefore dose-inefficient. Fused Full-field STEM (FF-STEM) is introduced as a 4D-STEM imaging modality that overcomes this limitation by combining ptychographic phase reconstruction with tilt-corrected dark-field imaging within a single acquisition. Bright-field data are used to estimate probe aberrations and reconstruct a high-resolution phase image, while dark-field data provide complementary low-frequency contrast. The two channels are optimally fused in Fourier space using minimum-variance weighting based on the spectral signal-to-noise ratio, yielding transfer-gap-free images with high contrast and quantitative fidelity. FF-STEM preserves the upsampling and depth-sectioning capabilities of ptychography, adds robust low-frequency contrast characteristic of dark-field imaging, and enables dose-efficient, near-real-time reconstruction.

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