发表机构
Stanford University; SLAC National Accelerator Laboratory（斯坦福大学; SLAC国家加速器实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对自支撑薄膜中的非均匀应变测量难题，提出弯曲轮廓电子断层扫描（BCET）计算框架，通过迭代优化损失函数从透射电镜图像定量重建二维应变与形貌，并在SrTiO3薄膜上验证了高保真度，为介观结构表征提供新方法。
AI 中文摘要
量子材料的自支撑薄膜自然会产生亚微米级、非均匀的应变场，这些应变场在平衡和非平衡条件下强烈影响其电子、磁性和结构性质。然而，当前定量解析这些介观特征的方法主要局限于扫描探针，这使得动态测量（如单次成像和飞秒显微镜）面临挑战。在此，我们提出一个新的计算框架，称为弯曲轮廓电子断层扫描（BCET），它能高效地将透射电子显微镜图像中的弯曲轮廓转换为定量的二维应变和形貌图。通过迭代最小化实验与模拟弯曲轮廓图像之间设计的损失函数，BCET无需扫描或衍射映射即可同时恢复表面形貌和面内应变张量场。我们将BCET应用于自支撑SrTiO$_3$薄膜，成功以高保真度重建了局部应变分布和曲率场。我们的方法为利用宽场成像表征自支撑薄膜中的介观结构提供了定量框架，为研究空间不均匀性如何调控二维量子材料中的相变和非平衡动力学开辟了新途径。
英文摘要
Freestanding thin films of quantum materials naturally develop sub-micrometer, nonuniform strain fields that strongly affect their electronic, magnetic, and structural properties in both equilibrium and nonequilibrium conditions. However, current methods to quantitatively resolve these mesoscopic features are primarily restricted to scanning probes, making it challenging for dynamical measurements such as single-shot imaging and femtosecond microscopy. Here, we present a new computational framework which we denote as bend contour electron tomography (BCET), which efficiently converts bend contours in transmission electron microscope images into quantitative two-dimensional maps of strain and topography. By iteratively minimizing a designed loss function between experimental and simulated bend contour images, BCET retrieves both surface morphology and in-plane strain tensor fields without requiring scanning or diffraction mapping. We applied BCET to freestanding SrTiO$_3$ thin films, demonstrating the successful reconstruction of the local strain distribution and curvature field with high fidelity. Our approach provides a quantitative framework for characterizing mesoscale structures in freestanding films using wide-field imaging, opening new avenues to investigate how spatial inhomogeneity governs phase transitions and nonequilibrium dynamics in two-dimensional quantum materials.
