Atom-by-atom Imaging of Moiré Phasons using Electron Ptychography
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arXiv
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| Auteurs principaux: | , , , , , , , , , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866913822500978688 |
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| author | Zhang, Yichao Ahammed, Ballal Bae, Sang Hyun Lee, Chia-Hao Huang, Jeffrey Hossain, Mohammad Abir Rakib, Tawfiqur van der Zande, Arend Ertekin, Elif Huang, Pinshane Y. |
| author_facet | Zhang, Yichao Ahammed, Ballal Bae, Sang Hyun Lee, Chia-Hao Huang, Jeffrey Hossain, Mohammad Abir Rakib, Tawfiqur van der Zande, Arend Ertekin, Elif Huang, Pinshane Y. |
| contents | Twisted 2D materials exhibit unique vibrational modes called moiré phonons, which arise from the moiré superlattice. Here, we demonstrate atom-by-atom imaging of phasons, an ultrasoft class of moiré phonons in twisted bilayer WSe2. Using ultrahigh-resolution (<15 pm) electron ptychography, we image the size and shape of each atom to extract time-averaged vibrational amplitudes as a function of twist angle and position. We observe several signature properties of moiré phasons, such as increased vibrational amplitudes at solitons and AA-stacked regions. By correlating experiments with molecular dynamics simulations and lattice dynamics calculations, we show phasons dominate the thermal vibrations in low-angle twisted bilayers. These results represent a powerful route to image thermal vibrations at atomic resolution, unlocking experimental studies of a thus-far hidden branch of moiré phonon physics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_03060 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Atom-by-atom Imaging of Moiré Phasons using Electron Ptychography Zhang, Yichao Ahammed, Ballal Bae, Sang Hyun Lee, Chia-Hao Huang, Jeffrey Hossain, Mohammad Abir Rakib, Tawfiqur van der Zande, Arend Ertekin, Elif Huang, Pinshane Y. Materials Science Twisted 2D materials exhibit unique vibrational modes called moiré phonons, which arise from the moiré superlattice. Here, we demonstrate atom-by-atom imaging of phasons, an ultrasoft class of moiré phonons in twisted bilayer WSe2. Using ultrahigh-resolution (<15 pm) electron ptychography, we image the size and shape of each atom to extract time-averaged vibrational amplitudes as a function of twist angle and position. We observe several signature properties of moiré phasons, such as increased vibrational amplitudes at solitons and AA-stacked regions. By correlating experiments with molecular dynamics simulations and lattice dynamics calculations, we show phasons dominate the thermal vibrations in low-angle twisted bilayers. These results represent a powerful route to image thermal vibrations at atomic resolution, unlocking experimental studies of a thus-far hidden branch of moiré phonon physics. |
| title | Atom-by-atom Imaging of Moiré Phasons using Electron Ptychography |
| topic | Materials Science |
| url | https://arxiv.org/abs/2505.03060 |