1
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Xie Y, Chalus N, Wang Z, Yao W, Liu J, Yao Y, White JS, DeBeer-Schmitt LM, Yin JX, Dai P, Eskildsen MR. Conventional superconductivity in the doped kagome superconductor Cs(V 0.86Ta 0.14) 3Sb 5 from vortex lattice studies. Nat Commun 2024; 15:6467. [PMID: 39085284 PMCID: PMC11291979 DOI: 10.1038/s41467-024-50856-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 07/22/2024] [Indexed: 08/02/2024] Open
Abstract
A hallmark of unconventional superconductors is a complex electronic phase diagram where intertwined orders of charge-spin-lattice degrees of freedom compete and coexist. While the kagome metals such as CsV3Sb5 also exhibit complex behavior, involving coexisting charge density wave order and superconductivity, much is unclear about the microscopic origin of the superconducting pairing. We study the vortex lattice in the superconducting state of Cs(V0.86Ta0.14)3Sb5, where the Ta-doping suppresses charge order and enhances superconductivity. Using small-angle neutron scattering, a strictly bulk probe, we show that the vortex lattice exhibits a strikingly conventional behavior. This includes a triangular symmetry with a period consistent with 2e-pairing, a field dependent scattering intensity that follows a London model, and a temperature dependence consistent with a uniform superconducting gap. Our results suggest that optimal bulk superconductivity in Cs(V1-xTax)3Sb5 arises from a conventional Bardeen-Cooper-Schrieffer electron-lattice coupling, different from spin fluctuation mediated unconventional copper- and iron-based superconductors.
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Affiliation(s)
- Yaofeng Xie
- Department of Physics and Astronomy, Rice University, Houston, TX, USA
| | - Nathan Chalus
- Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN, USA
| | - Zhiwei Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, China
| | - Weiliang Yao
- Department of Physics and Astronomy, Rice University, Houston, TX, USA
| | - Jinjin Liu
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, China
| | - Jonathan S White
- Laboratory for Neutron Scattering and Imaging (LNS), PSI Center for Neutron and Muon Sciences, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Lisa M DeBeer-Schmitt
- Large Scale Structures Section, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Jia-Xin Yin
- Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, TX, USA
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2
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Hu B, Chen H, Ye Y, Huang Z, Han X, Zhao Z, Xiao H, Lin X, Yang H, Wang Z, Gao HJ. Evidence of a distinct collective mode in Kagome superconductors. Nat Commun 2024; 15:6109. [PMID: 39030195 PMCID: PMC11271580 DOI: 10.1038/s41467-024-50330-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 07/05/2024] [Indexed: 07/21/2024] Open
Abstract
The collective modes of the superconducting order parameter fluctuation can provide key insights into the nature of the superconductor. Recently, a family of superconductors has emerged in non-magnetic kagome materials AV3Sb5 (A = K, Rb, Cs), exhibiting fertile emergent phenomenology. However, the collective behaviors of Cooper pairs have not been studied. Here, we report a distinct collective mode in CsV3-xTaxSb5 using scanning tunneling microscope/spectroscopy. The spectral line-shape is well-described by one isotropic and one anisotropic superconducting gap, and a bosonic mode due to electron-mode coupling. With increasing x, the two gaps move closer in energy, merge into two isotropic gaps of equal amplitude, and then increase synchronously. The mode energy decreases monotonically to well below 2 Δ and survives even after the charge density wave order is suppressed. We propose the interpretation of this collective mode as Leggett mode between different superconducting components or the Bardasis-Schrieffer mode due to a subleading superconducting component.
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Affiliation(s)
- Bin Hu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Hui Chen
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
- Hefei National Laboratory, 230088, Hefei, Anhui, PR China
| | - Yuhan Ye
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Zihao Huang
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Xianghe Han
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Zhen Zhao
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Hongqin Xiao
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Xiao Lin
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Haitao Yang
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China
| | - Ziqiang Wang
- Department of Physics, Boston College, Chestnut Hill, MA, 02467, USA.
| | - Hong-Jun Gao
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, PR China.
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, PR China.
- Hefei National Laboratory, 230088, Hefei, Anhui, PR China.
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3
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Le T, Pan Z, Xu Z, Liu J, Wang J, Lou Z, Yang X, Wang Z, Yao Y, Wu C, Lin X. Superconducting diode effect and interference patterns in kagome CsV 3Sb 5. Nature 2024; 630:64-69. [PMID: 38750364 DOI: 10.1038/s41586-024-07431-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 04/16/2024] [Indexed: 06/07/2024]
Abstract
The interplay among frustrated lattice geometry, non-trivial band topology and correlation yields rich quantum states of matter in kagome systems1,2. A series of recent members in this family, AV3Sb5 (A = K, Rb or Cs), exhibit a cascade of symmetry-breaking transitions3, involving the 3Q chiral charge ordering4-8, electronic nematicity9,10, roton pair density wave11 and superconductivity12. The nature of the superconducting order is yet to be resolved. Here we report an indication of dynamic superconducting domains with boundary supercurrents in intrinsic CsV3Sb5 flakes. The magnetic field-free superconducting diode effect is observed with polarity modulated by thermal histories, suggesting that there are dynamic superconducting order domains in a spontaneous time-reversal symmetry-breaking background. Strikingly, the critical current exhibits double-slit superconductivity interference patterns when subjected to an external magnetic field. The characteristics of the patterns are modulated by thermal cycling. These phenomena are proposed as a consequence of periodically modulated supercurrents flowing along certain domain boundaries constrained by fluxoid quantization. Our results imply a time-reversal symmetry-breaking superconducting order, opening a potential for exploring exotic physics, for example, Majorana zero modes, in this intriguing topological kagome system.
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Affiliation(s)
- Tian Le
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China
| | - Zhiming Pan
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China
- Institute for Theoretical Sciences, Westlake University, Hangzhou, China
| | - Zhuokai Xu
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China
| | - Jinjin Liu
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Jialu Wang
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China
| | - Zhefeng Lou
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China
| | - Xiaohui Yang
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China
- Department of Physics, China Jiliang University, Hangzhou, People's Republic of China
| | - Zhiwei Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China.
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China.
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, China.
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, China
| | - Congjun Wu
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China.
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China.
- Institute for Theoretical Sciences, Westlake University, Hangzhou, China.
- New Cornerstone Science Laboratory, Department of Physics, School of Science, Westlake University, Hangzhou, China.
| | - Xiao Lin
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, People's Republic of China.
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, People's Republic of China.
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4
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Liu J, Li Q, Li Y, Fan X, Li J, Zhu P, Deng H, Yin JX, Yang H, Li J, Wen HH, Wang Z. Enhancement of superconductivity and phase diagram of Ta-doped Kagome superconductor CsV 3Sb 5. Sci Rep 2024; 14:9580. [PMID: 38671053 PMCID: PMC11052999 DOI: 10.1038/s41598-024-59518-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
Kagome superconductors AV3Sb5 (A = K, Rb, and Cs) have attracted enormous interest due to the coexistence of charge density wave (CDW) order, unconventional superconductivity (SC) and anomalous Hall effect (AHE). In this paper, we reported an intensive investigation on Cs(V1-xTax)3Sb5 single crystals with systematic Ta doping. Ta was confirmed to be doped into V-site in the Kagome layer from both single crystal X-ray diffraction structural refinement and scanning transmission electron microscopy observation. The highest Ta doping level was found to be about 16%, which is more than twice as much as 7% in Nb-doped CsV3Sb5. With the increase of Ta doping, CDW order was gradually suppressed and finally vanished when the doping level reached to more than 8%. Meanwhile, superconductivity was enhanced with a maximum critical temperature (Tc) of 5.3 K, which is the highest Tc in the bulk crystal of this Kagome system at ambient pressure so far. The μ0Hc2(T) behavior demonstrates that the system is still a two-band superconductor after Ta doping. Based on the electrical transport measurement, a phase diagram was set up to exhibit the evolution of CDW and SC in the Cs(V1-xTax)3Sb5 system. These findings pave a new way to search for new superconductors with higher Tc in the AV3Sb5 family and establish a new platform for tuning and controlling the multiple orders and superconducting states.
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Affiliation(s)
- Jinjin Liu
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Qing Li
- National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Yongkai Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, 314011, People's Republic of China
| | - Xinwei Fan
- National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Jun Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
| | - Peng Zhu
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, 314011, People's Republic of China
| | - Hanbin Deng
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, People's Republic of China
| | - Jia-Xin Yin
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, People's Republic of China
| | - Huaixin Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China
| | - Jianqi Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China
| | - Hai-Hu Wen
- National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China.
| | - Zhiwei Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, 314011, People's Republic of China.
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5
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Fukushima K, Obata K, Yamane S, Hu Y, Li Y, Yao Y, Wang Z, Maeno Y, Yonezawa S. Violation of emergent rotational symmetry in the hexagonal Kagome superconductor CsV 3Sb 5. Nat Commun 2024; 15:2888. [PMID: 38605015 PMCID: PMC11009250 DOI: 10.1038/s41467-024-47043-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/12/2024] [Indexed: 04/13/2024] Open
Abstract
Superconductivity is caused by electron pairs that are canonically isotropic, whereas some exotic superconductors are known to exhibit non-trivial anisotropy stemming from unconventional pairings. However, superconductors with hexagonal symmetry, the highest rotational symmetry allowed in crystals, exceptionally have strong constraint that is called emergent rotational symmetry (ERS): anisotropic properties should be very weak especially near the critical temperature Tc even for unconventional pairings such as d-wave states. Here, we investigate superconducting anisotropy of the recently-found hexagonal Kagome superconductor CsV3Sb5, which is known to exhibit various intriguing phenomena originating from its undistorted Kagome lattice formed by vanadium atoms. Based on calorimetry performed under accurate two-axis field-direction control, we discover a combination of six- and two-fold anisotropies in the in-plane upper critical field. Both anisotropies, robust up to very close to Tc, are beyond predictions of standard theories. We infer that this clear ERS violation with nematicity is best explained by multi-component nematic superconducting order parameter in CsV3Sb5 intertwined with symmetry breakings caused by the underlying charge-density-wave order.
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Affiliation(s)
- Kazumi Fukushima
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Keito Obata
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Soichiro Yamane
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
- Department of Electronic Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - Yajian Hu
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Yongkai Li
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, P. R. China
- Material Science Center, Yangtze Delta Region Academy, Beijing Institute of Technology, Jiaxing, 314011, P. R. China
| | - Yugui Yao
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Zhiwei Wang
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China.
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, P. R. China.
- Material Science Center, Yangtze Delta Region Academy, Beijing Institute of Technology, Jiaxing, 314011, P. R. China.
| | - Yoshiteru Maeno
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
- Toyota Riken-Kyoto University Research Center (TRiKUC), Kyoto University, Kyoto, 606-8501, Japan
| | - Shingo Yonezawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan.
- Department of Electronic Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan.
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6
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Tazai R, Yamakawa Y, Kontani H. Drastic magnetic-field-induced chiral current order and emergent current-bond-field interplay in kagome metals. Proc Natl Acad Sci U S A 2024; 121:e2303476121. [PMID: 38207076 PMCID: PMC10801867 DOI: 10.1073/pnas.2303476121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 11/22/2023] [Indexed: 01/13/2024] Open
Abstract
In kagome metals, the chiral current order parameter [Formula: see text] with time-reversal-symmetry-breaking is the source of various exotic electronic states, while the method of controlling the current order and its interplay with the star-of-David bond order [Formula: see text] are still unsolved. Here, we reveal that tiny uniform orbital magnetization [Formula: see text] is induced by the chiral current order, and its magnitude is prominently enlarged under the presence of the bond order. Importantly, we derive the magnetic-field ([Formula: see text])-induced Ginzburg-Landau (GL) free energy expression [Formula: see text], which enables us to elucidate the field-induced current-bond phase transitions in kagome metals. The emergent current-bond-[Formula: see text] trilinear coupling term in the free energy, [Formula: see text], naturally explains the characteristic magnetic-field sensitive electronic states in kagome metals, such as the field-induced current order and the strong interplay between the bond and current orders. The GL coefficients of [Formula: see text] derived from the realistic multiorbital model are appropriate to explain various experiments. Furthermore, we discuss the field-induced loop current orders in the square lattice models that have been studied in cuprate superconductors.
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Affiliation(s)
- Rina Tazai
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto606-8502, Japan
| | | | - Hiroshi Kontani
- Department of Physics, Nagoya University, Nagoya464-8602, Japan
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7
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Tazai R, Yamakawa Y, Kontani H. Charge-loop current order and Z 3 nematicity mediated by bond order fluctuations in kagome metals. Nat Commun 2023; 14:7845. [PMID: 38030600 PMCID: PMC10687221 DOI: 10.1038/s41467-023-42952-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/25/2023] [Indexed: 12/01/2023] Open
Abstract
Recent experiments on geometrically frustrated kagome metal AV3Sb5 (A = K, Rb, Cs) have revealed the emergence of the charge loop current (cLC) order near the bond order (BO) phase. However, the origin of the cLC and its interplay with other phases have been uncovered. Here, we propose a novel mechanism of the cLC state, by focusing on the BO phase common in kagome metals. The BO fluctuations in kagome metals, which emerges due to the Coulomb interaction and the electron-phonon coupling, mediate the odd-parity particle-hole condensation that gives rise to the topological current order. Furthermore, the predicted cLC+BO phase gives rise to the Z3-nematic state in addition to the giant anomalous Hall effect. The present theory predicts the close relationship between the cLC, the BO, and the nematicity, which is significant to understand the cascade of quantum electron states in kagome metals. The present scenario provides a natural understanding.
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Grants
- JP20K22328 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22K14003 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP19H05825 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20K03858 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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Affiliation(s)
- Rina Tazai
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, 606-8502, Japan.
| | - Youichi Yamakawa
- Department of Physics, Nagoya University, Furo-cho, Nagoya, 464-8602, Japan
| | - Hiroshi Kontani
- Department of Physics, Nagoya University, Furo-cho, Nagoya, 464-8602, Japan
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8
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Zhang W, Liu X, Wang L, Tsang CW, Wang Z, Lam ST, Wang W, Xie J, Zhou X, Zhao Y, Wang S, Tallon J, Lai KT, Goh SK. Nodeless Superconductivity in Kagome Metal CsV 3Sb 5 with and without Time Reversal Symmetry Breaking. NANO LETTERS 2023; 23:872-879. [PMID: 36662599 PMCID: PMC9912374 DOI: 10.1021/acs.nanolett.2c04103] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/13/2023] [Indexed: 06/17/2023]
Abstract
The kagome metal CsV3Sb5 features an unusual competition between the charge-density-wave (CDW) order and superconductivity. Evidence for time reversal symmetry breaking (TRSB) inside the CDW phase has been accumulating. Hence, the superconductivity in CsV3Sb5 emerges from a TRSB normal state, potentially resulting in an exotic superconducting state. To reveal the pairing symmetry, we first investigate the effect of nonmagnetic impurity. Our results show that the superconducting critical temperature is insensitive to disorder, pointing to conventional s-wave superconductivity. Moreover, our measurements of the self-field critical current (Ic,sf), which is related to the London penetration depth, also confirm conventional s-wave superconductivity with strong coupling. Finally, we measure Ic,sf where the CDW order is removed by pressure and superconductivity emerges from the pristine normal state. Our results show that s-wave gap symmetry is retained, providing strong evidence for the presence of conventional s-wave superconductivity in CsV3Sb5 irrespective of the presence of the TRSB.
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Affiliation(s)
- Wei Zhang
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Xinyou Liu
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Lingfei Wang
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Chun Wai Tsang
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Zheyu Wang
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Siu Tung Lam
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Wenyan Wang
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Jianyu Xie
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
| | - Xuefeng Zhou
- Department
of Physics, Southern University of Science
and Technology, Shenzhen, Guangdong518055, China
| | - Yusheng Zhao
- Department
of Physics, Southern University of Science
and Technology, Shenzhen, Guangdong518055, China
| | - Shanmin Wang
- Department
of Physics, Southern University of Science
and Technology, Shenzhen, Guangdong518055, China
| | - Jeff Tallon
- Robinson
Institute, Victoria University of Wellington, P.O. Box 600, Wellington6140, New Zealand
| | - Kwing To Lai
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
- Shenzhen
Research Institute, The Chinese University
of Hong Kong, Shatin, Hong Kong, China
| | - Swee K. Goh
- Department
of Physics, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
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