Soft Phonon Charge-Density Wave Formation in the Kagome Metal KV$_3$Sb$_5$
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arXiv
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| Autori principali: | , , , , , , , , , , , , , |
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| Natura: | Preprint |
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2025
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| _version_ | 1866917381362679808 |
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| author | Wang, Yifan Xu, Chenchao Wu, Zhimian Rao, Huachen Shan, Zhaoyang Liu, Yi Cao, Guanghan Smidman, Michael Shi, Ming Yuan, Huiqiu Wu, Tao Chen, Xianhui Cao, Chao Song, Yu |
| author_facet | Wang, Yifan Xu, Chenchao Wu, Zhimian Rao, Huachen Shan, Zhaoyang Liu, Yi Cao, Guanghan Smidman, Michael Shi, Ming Yuan, Huiqiu Wu, Tao Chen, Xianhui Cao, Chao Song, Yu |
| contents | A range of of unusual emergent behaviors have been reported in the charge-density wave (CDW) state of the $A$V$_3$Sb$_5$ ($A=~$K, Rb, Cs) kagome metals, including a CDW formation process without soft phonons, which points to an unconventional CDW mechanism. Here, we use inelastic x-ray scattering to show that the CDW in KV$_3$Sb$_5$ forms via phonons that soften to zero energy at the CDW ordering vector ($L$-point) around $T_{\rm CDW}=78$~K. The intensity of soft phonons exhibit a remarkable in-plane anisotropy, extending over a much larger momentum range along $L$-$A$ relative to $L$-$H$, which leads to diffuse scattering common among $A$V$_3$Sb$_5$. Using first-principles calculations, we find that the momentum-dependent electron-phonon coupling (EPC) is peaked at $L$ and exhibits the same in-plane anisotropy as the phonon softening. Conversely, the electronic susceptibility is not peaked at $L$ and shows the opposite in-plane anisotropy. Our findings favor momentum-dependent EPC as the driving mechanism of the CDW in KV$_3$Sb$_5$, with a CDW formation process similar to that of transition metal dichalcogenides. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_20230 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Soft Phonon Charge-Density Wave Formation in the Kagome Metal KV$_3$Sb$_5$ Wang, Yifan Xu, Chenchao Wu, Zhimian Rao, Huachen Shan, Zhaoyang Liu, Yi Cao, Guanghan Smidman, Michael Shi, Ming Yuan, Huiqiu Wu, Tao Chen, Xianhui Cao, Chao Song, Yu Superconductivity Strongly Correlated Electrons A range of of unusual emergent behaviors have been reported in the charge-density wave (CDW) state of the $A$V$_3$Sb$_5$ ($A=~$K, Rb, Cs) kagome metals, including a CDW formation process without soft phonons, which points to an unconventional CDW mechanism. Here, we use inelastic x-ray scattering to show that the CDW in KV$_3$Sb$_5$ forms via phonons that soften to zero energy at the CDW ordering vector ($L$-point) around $T_{\rm CDW}=78$~K. The intensity of soft phonons exhibit a remarkable in-plane anisotropy, extending over a much larger momentum range along $L$-$A$ relative to $L$-$H$, which leads to diffuse scattering common among $A$V$_3$Sb$_5$. Using first-principles calculations, we find that the momentum-dependent electron-phonon coupling (EPC) is peaked at $L$ and exhibits the same in-plane anisotropy as the phonon softening. Conversely, the electronic susceptibility is not peaked at $L$ and shows the opposite in-plane anisotropy. Our findings favor momentum-dependent EPC as the driving mechanism of the CDW in KV$_3$Sb$_5$, with a CDW formation process similar to that of transition metal dichalcogenides. |
| title | Soft Phonon Charge-Density Wave Formation in the Kagome Metal KV$_3$Sb$_5$ |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2510.20230 |