Switchable half-quantum flux states in a ring of the kagome superconductor CsV$_3$Sb$_5$
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| Autores principales: | , , , , , , , , , , , , , , , , |
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| Formato: | Preprint |
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2025
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| _version_ | 1866909964313821184 |
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| author | Wang, Shuo Maccari, Ilaria Feng, Xilin Wu, Ze-Nan Peng, Jia-Peng Law, Kam Tuen Zhao, Y. X. Szabo, Andras Schnyder, Andreas Kang, Ning Wu, Xiao-Song Liu, Jingchao Fu, Xuewen Fischer, Mark H. Sigrist, Manfred Yu, Dapeng Lin, Ben-Chuan |
| author_facet | Wang, Shuo Maccari, Ilaria Feng, Xilin Wu, Ze-Nan Peng, Jia-Peng Law, Kam Tuen Zhao, Y. X. Szabo, Andras Schnyder, Andreas Kang, Ning Wu, Xiao-Song Liu, Jingchao Fu, Xuewen Fischer, Mark H. Sigrist, Manfred Yu, Dapeng Lin, Ben-Chuan |
| contents | Magnetic flux quantization in units of $Φ_0 = h/2e$ is a defining feature of superconductivity, rooted in the charge-2e nature of Cooper pairs. In a ring geometry, the flux quantization leads to oscillations in the critical temperature with magnetic flux, known as the Little-Parks effect. While the maximal critical temperature is conventionally at zero flux, departures from this rule, for instance shifts by a half-quantum flux $Φ_0/2$, clearly signal unconventional superconducting states and require sign-changing order parameters. Historically, such $π$-phase shifts in Little-Parks oscillations have been found in tricrystals or engineered ring structures that intentionally incorporate a $π$-phase shift. Here we report the discovery of switchable half-quantum flux states in rings made from single crystals of the kagome superconductor CsV$_3$Sb$_5$. We observe Little-Parks oscillations with a $π$-phase shift at zero bias current, which can be reversibly tuned to conventional Little-Parks oscillations upon applying a bias current. Between the $π$-phase and 0-phase regimes, $h/4e$ periodic oscillations appear. Our observations suggest unconventional pairing, potentially in the form of a multicomponent order parameter in the kagome superconductor CsV$_3$Sb$_5$, and reveal an electrically tunable landscape of competing superconducting condensates and fractional flux states. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_10010 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Switchable half-quantum flux states in a ring of the kagome superconductor CsV$_3$Sb$_5$ Wang, Shuo Maccari, Ilaria Feng, Xilin Wu, Ze-Nan Peng, Jia-Peng Law, Kam Tuen Zhao, Y. X. Szabo, Andras Schnyder, Andreas Kang, Ning Wu, Xiao-Song Liu, Jingchao Fu, Xuewen Fischer, Mark H. Sigrist, Manfred Yu, Dapeng Lin, Ben-Chuan Superconductivity Strongly Correlated Electrons Magnetic flux quantization in units of $Φ_0 = h/2e$ is a defining feature of superconductivity, rooted in the charge-2e nature of Cooper pairs. In a ring geometry, the flux quantization leads to oscillations in the critical temperature with magnetic flux, known as the Little-Parks effect. While the maximal critical temperature is conventionally at zero flux, departures from this rule, for instance shifts by a half-quantum flux $Φ_0/2$, clearly signal unconventional superconducting states and require sign-changing order parameters. Historically, such $π$-phase shifts in Little-Parks oscillations have been found in tricrystals or engineered ring structures that intentionally incorporate a $π$-phase shift. Here we report the discovery of switchable half-quantum flux states in rings made from single crystals of the kagome superconductor CsV$_3$Sb$_5$. We observe Little-Parks oscillations with a $π$-phase shift at zero bias current, which can be reversibly tuned to conventional Little-Parks oscillations upon applying a bias current. Between the $π$-phase and 0-phase regimes, $h/4e$ periodic oscillations appear. Our observations suggest unconventional pairing, potentially in the form of a multicomponent order parameter in the kagome superconductor CsV$_3$Sb$_5$, and reveal an electrically tunable landscape of competing superconducting condensates and fractional flux states. |
| title | Switchable half-quantum flux states in a ring of the kagome superconductor CsV$_3$Sb$_5$ |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2512.10010 |