A Strongly Anisotropic Superconducting Gap in the Kagome Superconductor CsV$_3$Sb$_5$: A Study of Directional Point-Contact Andreev Reflection Spectroscopy
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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_ | 1866911142423560192 |
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| author | Zhao, Yu-qing Wu, Zhi-fan Zuo, Hai-yan Lao, Weiming Yang, Wangju Chen, Qiuxia He, Yao Wang, Hai Yin, Qiangwei Wang, Qi Qi, Yang-peng Mu, Gang Lei, He-chang Ren, Cong |
| author_facet | Zhao, Yu-qing Wu, Zhi-fan Zuo, Hai-yan Lao, Weiming Yang, Wangju Chen, Qiuxia He, Yao Wang, Hai Yin, Qiangwei Wang, Qi Qi, Yang-peng Mu, Gang Lei, He-chang Ren, Cong |
| contents | In the recently discovered V-based kagome superconductors AV$_3$Sb$_5$ (A = K, Rb, and Cs), superconductivity is intertwined with an unconventional charge density wave (CDW) order, raising a fundamental concern on the superconducting gap structure of such kagome superconductors in the presence of CDW orders. Here, we report directional soft point-contact Andreev reflection (SPCAR) spectroscopy measurements on the kagome superconductor CsV$_3$Sb$_5$, revealing compelling evidence for the existence of a strongly anisotropic superconducting gap pairing state. The SPCAR spectra measured with current injected parallel to the $ab$-plane exhibit an in-gap single conductance peak, in contrast to those of SPCAR spectra: a double-peak structure in the perpendicular direction. These spectra are well described by an anisotropic single-gap BTK model. The extracted superconducting gaps comprise an isotropic large gap and a strongly anisotropic gap, originating from different Fermi surface sheets. Quantitative analysis reveals an anisotropy around $\ sim$70\% with a gap minimum of about 0.15 meV. These results shed new light on the unconventional multiband pairing states in kagome superconductors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_06066 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A Strongly Anisotropic Superconducting Gap in the Kagome Superconductor CsV$_3$Sb$_5$: A Study of Directional Point-Contact Andreev Reflection Spectroscopy Zhao, Yu-qing Wu, Zhi-fan Zuo, Hai-yan Lao, Weiming Yang, Wangju Chen, Qiuxia He, Yao Wang, Hai Yin, Qiangwei Wang, Qi Qi, Yang-peng Mu, Gang Lei, He-chang Ren, Cong Superconductivity In the recently discovered V-based kagome superconductors AV$_3$Sb$_5$ (A = K, Rb, and Cs), superconductivity is intertwined with an unconventional charge density wave (CDW) order, raising a fundamental concern on the superconducting gap structure of such kagome superconductors in the presence of CDW orders. Here, we report directional soft point-contact Andreev reflection (SPCAR) spectroscopy measurements on the kagome superconductor CsV$_3$Sb$_5$, revealing compelling evidence for the existence of a strongly anisotropic superconducting gap pairing state. The SPCAR spectra measured with current injected parallel to the $ab$-plane exhibit an in-gap single conductance peak, in contrast to those of SPCAR spectra: a double-peak structure in the perpendicular direction. These spectra are well described by an anisotropic single-gap BTK model. The extracted superconducting gaps comprise an isotropic large gap and a strongly anisotropic gap, originating from different Fermi surface sheets. Quantitative analysis reveals an anisotropy around $\ sim$70\% with a gap minimum of about 0.15 meV. These results shed new light on the unconventional multiband pairing states in kagome superconductors. |
| title | A Strongly Anisotropic Superconducting Gap in the Kagome Superconductor CsV$_3$Sb$_5$: A Study of Directional Point-Contact Andreev Reflection Spectroscopy |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2509.06066 |