Spatial correlations of charge density wave order across the transition in 2H-NbSe2
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arXiv
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| Autores principales: | , , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866911356654977024 |
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| author | Hong, Seokjo Oh, Jaewhan Park, Jemin Cho, Woohyun Lee, Soyoung Ophus, Colin Kim, Yeongkwan Yang, Heejun Lee, SungBin Yang, Yongsoo |
| author_facet | Hong, Seokjo Oh, Jaewhan Park, Jemin Cho, Woohyun Lee, Soyoung Ophus, Colin Kim, Yeongkwan Yang, Heejun Lee, SungBin Yang, Yongsoo |
| contents | Charge density waves (CDWs) involve coupled amplitude and phase degrees of freedom, but direct access to local amplitude correlations remains experimentally challenging. Here, we report cryogenic four-dimensional scanning transmission electron microscopy (4D-STEM) measurements of CDW ordering in a 2H-NbSe2 flake of 24 nm thickness, enabled by liquid helium-based cooling. By mapping the spatial distribution of CDW superlattice intensities at nanometer-scale resolution and analyzing their autocorrelations, we extract the temperature-dependent correlation length associated with the local amplitude of the CDW order parameter, independent of global phase coherence. Our results reveal that a finite local CDW amplitude is already established well above the transition temperature. When the system is cooled below the transition temperature down to 20 K, the correlation length extends to nearly 110 nm, and the local CDW amplitude is found to strongly anticorrelate with the local strain field. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_02991 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Spatial correlations of charge density wave order across the transition in 2H-NbSe2 Hong, Seokjo Oh, Jaewhan Park, Jemin Cho, Woohyun Lee, Soyoung Ophus, Colin Kim, Yeongkwan Yang, Heejun Lee, SungBin Yang, Yongsoo Strongly Correlated Electrons Materials Science Charge density waves (CDWs) involve coupled amplitude and phase degrees of freedom, but direct access to local amplitude correlations remains experimentally challenging. Here, we report cryogenic four-dimensional scanning transmission electron microscopy (4D-STEM) measurements of CDW ordering in a 2H-NbSe2 flake of 24 nm thickness, enabled by liquid helium-based cooling. By mapping the spatial distribution of CDW superlattice intensities at nanometer-scale resolution and analyzing their autocorrelations, we extract the temperature-dependent correlation length associated with the local amplitude of the CDW order parameter, independent of global phase coherence. Our results reveal that a finite local CDW amplitude is already established well above the transition temperature. When the system is cooled below the transition temperature down to 20 K, the correlation length extends to nearly 110 nm, and the local CDW amplitude is found to strongly anticorrelate with the local strain field. |
| title | Spatial correlations of charge density wave order across the transition in 2H-NbSe2 |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2506.02991 |