Large Kohn anomaly and phonon collapse induced by charge density wave in UPt$_2$Si$_2$
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| Main Authors: | , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866918096679206912 |
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| author | Lee, Jooseop Chappell, Greta L. Baumbach, Ryan E. Said, Ayman H. Zaliznyak, Igor A. |
| author_facet | Lee, Jooseop Chappell, Greta L. Baumbach, Ryan E. Said, Ayman H. Zaliznyak, Igor A. |
| contents | Using high-energy-resolution inelastic x-ray scattering, we observe anomalous softening and damping of the transverse acoustic phonon in UPt$_2$Si$_2$ as the system is cooled towards the charge density wave (CDW) transition temperature, T$_{\rm{CDW}}$. The phonon exhibits a marked Kohn-type anomaly around the CDW wave vector, Q$_{\rm{CDW}}$, and becomes overdamped within a finite momentum range already well above T$_{\rm{CDW}}$. The dispersion anomaly is consistent with potential Fermi surface nesting, which together with the extended phonon collapse indicate strong electron-phonon coupling. The transition temperature estimated from the phonon softening is markedly lower than T$_{\rm{CDW}}$, consistent with a primarily electronic instability rather than a phonon-driven transition. Our results establish UPt$_2$Si$_2$ as a prime example of a strongly correlated electron CDW system with exceptionally strong electron-phonon coupling driving phonon softening and collapse. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_10346 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Large Kohn anomaly and phonon collapse induced by charge density wave in UPt$_2$Si$_2$ Lee, Jooseop Chappell, Greta L. Baumbach, Ryan E. Said, Ayman H. Zaliznyak, Igor A. Strongly Correlated Electrons Using high-energy-resolution inelastic x-ray scattering, we observe anomalous softening and damping of the transverse acoustic phonon in UPt$_2$Si$_2$ as the system is cooled towards the charge density wave (CDW) transition temperature, T$_{\rm{CDW}}$. The phonon exhibits a marked Kohn-type anomaly around the CDW wave vector, Q$_{\rm{CDW}}$, and becomes overdamped within a finite momentum range already well above T$_{\rm{CDW}}$. The dispersion anomaly is consistent with potential Fermi surface nesting, which together with the extended phonon collapse indicate strong electron-phonon coupling. The transition temperature estimated from the phonon softening is markedly lower than T$_{\rm{CDW}}$, consistent with a primarily electronic instability rather than a phonon-driven transition. Our results establish UPt$_2$Si$_2$ as a prime example of a strongly correlated electron CDW system with exceptionally strong electron-phonon coupling driving phonon softening and collapse. |
| title | Large Kohn anomaly and phonon collapse induced by charge density wave in UPt$_2$Si$_2$ |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2412.10346 |