Unconventional gapping behavior in a kagome superconductor
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| Autores principales: | , , , , , , , , , , , , , , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2024
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| author | Hossain, Md Shafayat Zhang, Qi Choi, Eun Sang Ratkovski, Danilo Lüscher, Bernhard Li, Yongkai Jiang, Yu-Xiao Litskevich, Maksim Cheng, Zi-Jia Yin, Jia-Xin Cochran, Tyler A. Casas, Brian Kim, Byunghoon Yang, Xian Liu, Jinjin Yao, Yugui Bangura, Ali Wang, Zhiwei Fischer, Mark H. Neupert, Titus Balicas, Luis Hasan, M. Zahid |
| author_facet | Hossain, Md Shafayat Zhang, Qi Choi, Eun Sang Ratkovski, Danilo Lüscher, Bernhard Li, Yongkai Jiang, Yu-Xiao Litskevich, Maksim Cheng, Zi-Jia Yin, Jia-Xin Cochran, Tyler A. Casas, Brian Kim, Byunghoon Yang, Xian Liu, Jinjin Yao, Yugui Bangura, Ali Wang, Zhiwei Fischer, Mark H. Neupert, Titus Balicas, Luis Hasan, M. Zahid |
| contents | Determining the types of superconducting order in quantum materials is a challenge, especially when multiple degrees of freedom, such as bands or orbitals, contribute to the fermiology and when superconductivity competes, intertwines, or coexists with other symmetry-breaking orders. Here, we study the Kagome-lattice superconductor CsV3Sb5, in which multiband superconductivity coexists with a charge order that substantially reduces the compound's space group symmetries. Through a combination of thermodynamic as well as electrical and thermal transport measurements, we uncover two superconducting regimes with distinct transport and thermodynamic characteristics, while finding no evidence for a phase transition separating them. Thermodynamic measurements reveal substantial quasiparticle weight in a high-temperature regime. At lower temperatures, this weight is removed via the formation of a second gap. The two regimes are sharply distinguished by a pronounced enhancement of the upper critical field at low temperatures and by a switch in the anisotropy of the longitudinal thermal conductivity as a function of in-plane magnetic field orientation. We argue that the band with a gap opening at lower temperatures continues to host low-energy quasiparticles, possibly due to a nodal structure of the gap. Taken together, our results present evidence for band-selective superconductivity with remarkable decoupling of the (two) superconducting gaps. The commonly employed multiband scenario, whereby superconductivity emerges in a primary band and is then induced in other bands appears to fail in this unconventional kagome superconductor. Instead, band-selective superconducting pairing is a paradigm that seems to unify seemingly contradicting results in this intensely studied family of materials and beyond. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_15333 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Unconventional gapping behavior in a kagome superconductor Hossain, Md Shafayat Zhang, Qi Choi, Eun Sang Ratkovski, Danilo Lüscher, Bernhard Li, Yongkai Jiang, Yu-Xiao Litskevich, Maksim Cheng, Zi-Jia Yin, Jia-Xin Cochran, Tyler A. Casas, Brian Kim, Byunghoon Yang, Xian Liu, Jinjin Yao, Yugui Bangura, Ali Wang, Zhiwei Fischer, Mark H. Neupert, Titus Balicas, Luis Hasan, M. Zahid Strongly Correlated Electrons Mesoscale and Nanoscale Physics Materials Science Superconductivity Determining the types of superconducting order in quantum materials is a challenge, especially when multiple degrees of freedom, such as bands or orbitals, contribute to the fermiology and when superconductivity competes, intertwines, or coexists with other symmetry-breaking orders. Here, we study the Kagome-lattice superconductor CsV3Sb5, in which multiband superconductivity coexists with a charge order that substantially reduces the compound's space group symmetries. Through a combination of thermodynamic as well as electrical and thermal transport measurements, we uncover two superconducting regimes with distinct transport and thermodynamic characteristics, while finding no evidence for a phase transition separating them. Thermodynamic measurements reveal substantial quasiparticle weight in a high-temperature regime. At lower temperatures, this weight is removed via the formation of a second gap. The two regimes are sharply distinguished by a pronounced enhancement of the upper critical field at low temperatures and by a switch in the anisotropy of the longitudinal thermal conductivity as a function of in-plane magnetic field orientation. We argue that the band with a gap opening at lower temperatures continues to host low-energy quasiparticles, possibly due to a nodal structure of the gap. Taken together, our results present evidence for band-selective superconductivity with remarkable decoupling of the (two) superconducting gaps. The commonly employed multiband scenario, whereby superconductivity emerges in a primary band and is then induced in other bands appears to fail in this unconventional kagome superconductor. Instead, band-selective superconducting pairing is a paradigm that seems to unify seemingly contradicting results in this intensely studied family of materials and beyond. |
| title | Unconventional gapping behavior in a kagome superconductor |
| topic | Strongly Correlated Electrons Mesoscale and Nanoscale Physics Materials Science Superconductivity |
| url | https://arxiv.org/abs/2411.15333 |