The realization of chromatic aberration correction enables energy-filtered transmission electron microscopy (EFTEM) at atomic resolution even for large energy windows. Previous works have demonstrated lattice contrast from ionization-edge signals such as the L2,3 edges of silicon or titanium. However, the direct interpretation as chemical information was found to be hampered by contributions from elastic contrast with dynamic scattering, especially for thick samples. Here we demonstrate that even for thin samples with light atoms, the interpretation of the ionization-edge signal is complicated by inversions from bright-atom to dark-atom contrast. Our EFTEM experiments for graphene show lattice contrast in the carbon K-edge signal, and we find bright-atom and dark-atom contrast for different defoci.

中文翻译：

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石墨烯磁芯损耗 EFTEM 信号的晶格对比

色差校正的实现使能量过滤透射电子显微镜 (EFTEM) 在原子分辨率下成为可能，即使对于大能量窗口也是如此。以前的工作已经证明了来自电离边缘信号的晶格对比度，例如硅或钛的 L2,3 边缘。然而，发现弹性对比与动态散射的贡献阻碍了作为化学信息的直接解释，特别是对于厚样品。在这里，我们证明，即使对于具有轻原子的薄样品，电离边缘信号的解释也会因从亮原子到暗原子对比度的反转而变得复杂。我们对石墨烯的 EFTEM 实验显示了碳 K 边缘信号中的晶格对比度，并且我们发现了不同离焦的亮原子和暗原子对比度。