Soft Mode Origin of Charge Ordering in Superconducting Kagome CsV$_3$Sb$_5$
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arXiv
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| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866908606301995008 |
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| author | McGuinness, Philippa Helen Henssler, Fabian Alkorta, Manex von Westarp, Mark Joachim Graf Korshunov, Artem Bosak, Alexei Ishikawa, Daisuke Baron, Alfred Q. R. Merz, Michael Haghighirad, Amir-Abbas Vergniory, Maia G. Souliou, Sofia-Michaela Heid, Rolf Errea, Ion Tacon, Matthieu Le |
| author_facet | McGuinness, Philippa Helen Henssler, Fabian Alkorta, Manex von Westarp, Mark Joachim Graf Korshunov, Artem Bosak, Alexei Ishikawa, Daisuke Baron, Alfred Q. R. Merz, Michael Haghighirad, Amir-Abbas Vergniory, Maia G. Souliou, Sofia-Michaela Heid, Rolf Errea, Ion Tacon, Matthieu Le |
| contents | Charge-density-wave (CDW) order and superconductivity coexist in the kagome metals AV$_3$Sb$_5$ (A=K, Cs, Rb), raising fundamental questions about the mechanisms driving their intertwined phases. Here we combine high-resolution inelastic X-ray scattering with first-principles calculations to uncover the origin of CDW formation in CsV$_3$Sb$_5$. Guided by structure factor analysis, we identify a soft phonon mode along the reciprocal M-L direction, with the strongest effect at the L point, where the elastic scattering intensity also grows most rapidly upon cooling. First-principles calculations incorporating lattice anharmonicity and electron-phonon coupling reproduce these observations and establish a soft-mode instability at the L point as the driving mechanism of CDW formation. Despite the weakly first-order character of the transition, our results unambiguously demonstrate that the CDW in CsV$_3$Sb$_5$ originates from a softened phonon, clarifying its microscopic origin and highlighting the central role of lattice dynamics in kagome metals. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2510_19790 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Soft Mode Origin of Charge Ordering in Superconducting Kagome CsV$_3$Sb$_5$ McGuinness, Philippa Helen Henssler, Fabian Alkorta, Manex von Westarp, Mark Joachim Graf Korshunov, Artem Bosak, Alexei Ishikawa, Daisuke Baron, Alfred Q. R. Merz, Michael Haghighirad, Amir-Abbas Vergniory, Maia G. Souliou, Sofia-Michaela Heid, Rolf Errea, Ion Tacon, Matthieu Le Superconductivity Strongly Correlated Electrons Charge-density-wave (CDW) order and superconductivity coexist in the kagome metals AV$_3$Sb$_5$ (A=K, Cs, Rb), raising fundamental questions about the mechanisms driving their intertwined phases. Here we combine high-resolution inelastic X-ray scattering with first-principles calculations to uncover the origin of CDW formation in CsV$_3$Sb$_5$. Guided by structure factor analysis, we identify a soft phonon mode along the reciprocal M-L direction, with the strongest effect at the L point, where the elastic scattering intensity also grows most rapidly upon cooling. First-principles calculations incorporating lattice anharmonicity and electron-phonon coupling reproduce these observations and establish a soft-mode instability at the L point as the driving mechanism of CDW formation. Despite the weakly first-order character of the transition, our results unambiguously demonstrate that the CDW in CsV$_3$Sb$_5$ originates from a softened phonon, clarifying its microscopic origin and highlighting the central role of lattice dynamics in kagome metals. |
| title | Soft Mode Origin of Charge Ordering in Superconducting Kagome CsV$_3$Sb$_5$ |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2510.19790 |