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Chin. Phys. B, 2026, Vol. 35(2): 027403    DOI: 10.1088/1674-1056/ae2c6d
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Exotic superconductivity in new topological kagome metal CsTi3Bi5

Jiali Liu(刘家利)1,2,†, Zhen Zhao(赵振)1,2,†, Hongqin Xiao(肖洪钦)1,2,†, Yuhang Zhang(张宇航)1,2, Zouyouwei Lu(鲁邹有为)1,2, Jihu Lu(卢佶虎)1,2, Feng Wu(吴凤)1,3, Chengjie Xu(徐诚杰)1,2, Hua Zhang(张华)1,2, Hui Chen(陈辉)1,2,‡, Haitao Yang(杨海涛)1,2,§, Ziyi Liu(刘子儀)1,2,¶, Xiaoli Dong(董晓莉)1,2,4, and Hongjun Gao(高鸿钧)1,2,#
1 Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China;
3 Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing 100081, China;
4 Songshan Lake Materials Laboratory, Dongguan 523808, China
Abstract  We present a systematic investigation of the superconductivity in high-quality CsTi$_{3}$Bi$_{5}$ single crystals by combining bulk property characterization and local-probe spectroscopy. Two successive superconducting transitions are observed in this newly discovered kagome material. In the first stage, the diamagnetic response strengthens significantly from $T_{\rm c} \sim 4.9 $ K to 4.6 K, followed by a broad transition below 4.6 K in the second stage. Moreover, different magnetic field dependences are observed for the two stages, where the first stage is field-insensitive while the second stage exhibits strong field dependence. The ultra-low magnetic field measurements indicate that the lower critical field $H_{\rm c1}(T)$ exhibits small anisotropy. Based on a comparative study of the superconducting state in CsBi$_{2}$ and microscopic verification via scanning tunneling microscopy (STM), our results suggest the emergence of exotic and intrinsic superconductivity in this new titanium-based kagome superconductor, establishing it as a promising platform for further exploring the complexity of electronic states in the kagome lattice.
Keywords:  kagome metal      titanium-based material      superconductivity      critical field  
Received:  11 November 2025      Revised:  22 November 2025      Accepted manuscript online:  15 December 2025
PACS:  74.70.Ad (Metals; alloys and binary compounds)  
  74.25.Op (Mixed states, critical fields, and surface sheaths)  
  71.20.Gj (Other metals and alloys)  
Fund: We acknowledge Prof. Hongjun Gao and Prof. Haitao Yang for their high-quality single crystals and insightful comments and Prof. Hui Chen for the assistance in STM measurements. This work was supported by the National Key Research and Development Program of China (Grant Nos. 2022YFA1403903, 2023YFA1406101, 2024YFA1611102, and 2022YFA1204100), the National Natural Science Foundation of China (Grant Nos. 12304075 and 62488201), CAS Project for Young Scientists in Basic Research (Grant Nos. 2022YSBR-048 and YSBR-003) and the Innovation Program of Quantum Science and Technology (Grant No. 2021ZD0302700).
Corresponding Authors:  Hui Chen, Haitao Yang, Ziyi Liu, Hongjun Gao     E-mail:  hchenn04@iphy.ac.cn;htyang@iphy.ac.cn;zy_liu@iphy.ac.cn;hjgao@iphy.ac.cn

Cite this article: 

Jiali Liu(刘家利), Zhen Zhao(赵振), Hongqin Xiao(肖洪钦), Yuhang Zhang(张宇航), Zouyouwei Lu(鲁邹有为), Jihu Lu(卢佶虎), Feng Wu(吴凤), Chengjie Xu(徐诚杰), Hua Zhang(张华), Hui Chen(陈辉), Haitao Yang(杨海涛), Ziyi Liu(刘子儀), Xiaoli Dong(董晓莉), and Hongjun Gao(高鸿钧) Exotic superconductivity in new topological kagome metal CsTi3Bi5 2026 Chin. Phys. B 35 027403

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