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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2505.04078 |
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| _version_ | 1866908353511292928 |
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| author | Li, Yangfan Pan, Yue Lei, Xincheng Chen, Weiwei Shen, Yang Ge, Mengshu Liu, Xiaozhi Su, Dong |
| author_facet | Li, Yangfan Pan, Yue Lei, Xincheng Chen, Weiwei Shen, Yang Ge, Mengshu Liu, Xiaozhi Su, Dong |
| contents | High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) is a vital tool for characterizing single-atom catalysts (SACs). However, reliable elemental identification of different atoms remains challenging because the signal intensity of HAADF depends strongly on defocus and other imaging parameters, potentially ruining the Z-contrast of atoms at different depths. In this work, we investigated the influence of the vertical position of atoms (defocus), support thickness, interatomic height, convergence and collection angles via multi-slice simulations on a model system of Fe/Pt atoms on amorphous carbon supports. Our calculation shows that at a convergence angle of 28 mrad, a defocus of 4.6 nm can cause Fe and Pt atoms indistinguishable. At a larger convergence angle, this critical indistinguishable defocus can be even shorter. To address this limitation, we propose a Multi-Defocus Fusion (MDF) method, retrieving the Z-contrast from serial images from multiple defocus. Experimental validation on a Fe/Pt SAC sample confirms the effectiveness of MDF, yielding clearly separated intensity histograms corresponding to Fe and Pt atoms. This work presents a robust, easy-to-implement strategy for accurate single-atom identification, offering valuable guidance for the accelerated screening and rational design of high-performance SACs. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_04078 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Differentiation of Distinct Single Atoms via Multi-Defocus Fusion Method Li, Yangfan Pan, Yue Lei, Xincheng Chen, Weiwei Shen, Yang Ge, Mengshu Liu, Xiaozhi Su, Dong Materials Science High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) is a vital tool for characterizing single-atom catalysts (SACs). However, reliable elemental identification of different atoms remains challenging because the signal intensity of HAADF depends strongly on defocus and other imaging parameters, potentially ruining the Z-contrast of atoms at different depths. In this work, we investigated the influence of the vertical position of atoms (defocus), support thickness, interatomic height, convergence and collection angles via multi-slice simulations on a model system of Fe/Pt atoms on amorphous carbon supports. Our calculation shows that at a convergence angle of 28 mrad, a defocus of 4.6 nm can cause Fe and Pt atoms indistinguishable. At a larger convergence angle, this critical indistinguishable defocus can be even shorter. To address this limitation, we propose a Multi-Defocus Fusion (MDF) method, retrieving the Z-contrast from serial images from multiple defocus. Experimental validation on a Fe/Pt SAC sample confirms the effectiveness of MDF, yielding clearly separated intensity histograms corresponding to Fe and Pt atoms. This work presents a robust, easy-to-implement strategy for accurate single-atom identification, offering valuable guidance for the accelerated screening and rational design of high-performance SACs. |
| title | Differentiation of Distinct Single Atoms via Multi-Defocus Fusion Method |
| topic | Materials Science |
| url | https://arxiv.org/abs/2505.04078 |