Journal Highlights
Techniques Development
Live Processing of Momentum-Resolved STEM Data for First Moment Imaging and Ptychography by A Strauch, D Weber, A Clausen, A Lesnichaia, A Bangun, B März, FJ Lyu, Q Chen, A Rosenauer, R Dunin-Borkowski, and K Müller-Caspary, Microsc Microanal |
https://doi.org/10.1017/S1431927621012423.
A reformulated implementation of single-sideband
ptychography enables analysis and display of live detector data streams in momentum-resolved scanning transmission electron microscopy (STEM) using the LiberTEM open-source platform. Tis is combined with live first moment and further virtual STEM detector analysis. Processing of both real experimental and simulated data shows the characteristics of this method when data are processed progressively, as opposed to the usual offline processing of a complete data set. In particular, the single-sideband method is compared with other techniques, such as the enhanced ptychographic engine, in order to ascertain its capability for structural imaging at increased specimen thickness. Qualitatively interpretable live results are also obtained if the sample is moved, magnification is changed, or the focus is optimized during the analysis (Figure). Tis allows live optimization of an instrument as well as specimen parameters during the analysis. Te methodology is expected to improve contrast- and dose-efficient in situ imaging of weakly scattering specimens, where fast live feedback during the experiment is required.
Live single-sideband reconstruction of a momentum-resolved STEM scan on a SrTiO3
during the scan.
sample in [001] orientation. The focus was changed and optimized
Review Article
Advances and Applications of Atomic-Resolution Scanning Transmission Electron Microscopy by J Liu, Microsc Microanal |
https://doi.org/10.1017/S1431927621012125. Atomic-resolution scanning transmission electron micros-
copy (STEM) was realized more than 50 years ago. Te practi- cal realization of aberration correctors to form sub-Ångstrom electron probes on STEM instruments, however, significantly expanded the impact of STEM and associated diffraction and spectroscopy techniques on solving a wide range of challenging materials problems. Te flexibility in configuring STEM detec- tors to form the corresponding images makes the STEM instru- ment a versatile tool for exploring the intrinsic nature of matter with atomic-scale resolution, picometer precision, and single- atom chemical sensitivity for both heavy and light elements (Figure). Tis review provides an account of the development of STEM techniques with a focus on atomic-resolution imaging and its applications in materials characterization. Critical issues such as electron beam-induced effects and how to alleviate such effects are also highlighted. It is expected that ultrafast comput- ers and electron detectors, robust image acquisition and process- ing algorithms, machine learning, and artificial intelligence will all play an increasingly important role in acquiring, analyzing, and correlating STEM data to materials properties.
2021 November •
www.microscopy-today.com
Aberration-corrected high-angle annular dark-field STEM image of Ir single- atom chains on ZnO nanobelts. These single-atom chains are stable in air up to 600°C. These Ir atom chains demonstrated catalytic activity for carbon monoxide oxidation.
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