This article summarizes core aspects of beam-sample interactions in research that aims at exploiting the ability to detect single atoms at atomic resolution by mid-voltage transmission electron microscopy. Investigating the atomic structure of catalytic Co3O4 nanocrystals underscores how indispensable it is to rigorously control electron dose rates and total doses to understand native material properties on this scale. We apply in-line holography with variable dose rates to achieve this goal. Genuine object structures can be maintained if dose rates below ~100 e/Å2s are used and the contrast required for detection of single atoms is generated by capturing large image series. Threshold doses for the detection of single atoms are estimated. An increase of electron dose rates and total doses to common values for high resolution imaging of solids stimulates object excitations that restructure surfaces, interfaces, and defects and cause grain reorientation or growth. We observe a variety of previously unknown atom configurations in surface proximity of the Co3O4 spinel structure. These are hidden behind broadened diffraction patterns in reciprocal space but become visible in real space by solving the phase problem. An exposure of the Co3O4 spinel structure to water vapor or other gases induces drastic structure alterations that can be captured in this manner.

中文翻译：

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通过在透射电子显微镜的真空中控制射线诱导的样品变化来检测Co3O4催化剂的结构变化。

本文总结了研究中束-样品相互作用的核心方面，旨在利用中压透射电子显微镜利用原子分辨率检测单个原子的能力。研究催化性Co3O4纳米晶体的原子结构强调了严格控制电子剂量率和总剂量以了解这种规模的天然材料的特性是多么不可或缺。我们采用可变剂量率的在线全息照相技术来实现这一目标。如果使用低于〜100 e /Å2s的剂量率，并且通过捕获大图像序列来生成检测单个原子所需的对比度，则可以保持真正的对象结构。估计用于检测单个原子的阈值剂量。对于固体的高分辨率成像，将电子剂量率和总剂量增加到共同值会刺激物体激发，从而重新构造表面，界面和缺陷，并导致晶粒重新定向或生长。我们在Co3O4尖晶石结构的表面附近观察到各种先前未知的原子构型。这些隐藏在互易空间中加宽的衍射图样之后，但通过解决相位问题在实际空间中变得可见。Co3O4尖晶石结构暴露于水蒸气或其他气体会引起剧烈的结构变化，可以用这种方式捕获这种变化。这些隐藏在互易空间中加宽的衍射图样之后，但通过解决相位问题在实际空间中变得可见。Co3O4尖晶石结构暴露于水蒸气或其他气体会引起剧烈的结构变化，可以用这种方式捕获这种变化。这些隐藏在互易空间中加宽的衍射图样之后，但通过解决相位问题在实际空间中变得可见。Co3O4尖晶石结构暴露于水蒸气或其他气体会引起剧烈的结构变化，可以用这种方式捕获这种变化。