School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA.
Science. 2021 May 21;372(6544):826-831. doi: 10.1126/science.abg2533.
Transmission electron microscopes use electrons with wavelengths of a few picometers, potentially capable of imaging individual atoms in solids at a resolution ultimately set by the intrinsic size of an atom. However, owing to lens aberrations and multiple scattering of electrons in the sample, the image resolution is reduced by a factor of 3 to 10. By inversely solving the multiple scattering problem and overcoming the electron-probe aberrations using electron ptychography, we demonstrate an instrumental blurring of less than 20 picometers and a linear phase response in thick samples. The measured widths of atomic columns are limited by thermal fluctuations of the atoms. Our method is also capable of locating embedded atomic dopant atoms in all three dimensions with subnanometer precision from only a single projection measurement.
透射电子显微镜使用的电子波长短至几个皮米，理论上有可能在分辨率上达到单个原子的程度，其分辨率最终由原子的固有大小决定。然而，由于透镜像差和样品中电子的多次散射，图像分辨率降低了 3 到 10 倍。通过反演求解多次散射问题，并利用电子相衬技术克服电子探针像差，我们证明了仪器的模糊度小于 20 皮米，并且在厚样品中具有线性相位响应。原子列的测量宽度受原子热涨落的限制。我们的方法还能够仅通过单次投影测量，以亚纳米的精度在三个维度上定位嵌入的原子掺杂原子。
