Flat bands, non-trivial band topology and rotation symmetry breaking in layered kagome-lattice RbTi3Bi5

Zhicheng Jiang; Zhengtai Liu; Haiyang Ma; Wei Xia; Zhonghao Liu; Jishan Liu; Soohyun Cho; Yichen Yang; Jianyang Ding; Jiayu Liu; Zhe Huang; Yuxi Qiao; Jiajia Shen; Wenchuan Jing; Xiangqi Liu; Jianpeng Liu; Yanfeng Guo; Dawei Shen

doi:10.1038/s41467-023-40515-3

Flat bands, non-trivial band topology and rotation symmetry breaking in layered kagome-lattice RbTi₃Bi₅

Nat Commun. 2023 Aug 14;14(1):4892. doi: 10.1038/s41467-023-40515-3.

Authors

Zhicheng Jiang^#^{1

2}, Zhengtai Liu^#^{3

4}, Haiyang Ma^#^{5

6}, Wei Xia^#^{5

6}, Zhonghao Liu¹, Jishan Liu^{1

7}, Soohyun Cho¹, Yichen Yang¹, Jianyang Ding¹, Jiayu Liu¹, Zhe Huang⁵, Yuxi Qiao¹, Jiajia Shen¹, Wenchuan Jing¹, Xiangqi Liu^{6

8}, Jianpeng Liu^{9

10}, Yanfeng Guo^{11

12}, Dawei Shen^{13

14}

Affiliations

¹ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China.
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China.
³ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China. ztliu@mail.sim.ac.cn.
⁴ Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210, Shanghai, China. ztliu@mail.sim.ac.cn.
⁵ School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China.
⁶ ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China.
⁷ Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210, Shanghai, China.
⁸ National Synchrotron Radiation Laboratory, University of Science and Technology of China, 230029, Hefei, China.
⁹ School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China. liujp@shanghaitech.edu.cn.
¹⁰ ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China. liujp@shanghaitech.edu.cn.
¹¹ School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China. guoyf@shanghaitech.edu.cn.
¹² ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China. guoyf@shanghaitech.edu.cn.
¹³ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China. dwshen@ustc.edu.cn.
¹⁴ National Synchrotron Radiation Laboratory, University of Science and Technology of China, 230029, Hefei, China. dwshen@ustc.edu.cn.

^# Contributed equally.

Abstract

A representative class of kagome materials, AV₃Sb₅ (A = K, Rb, Cs), hosts several unconventional phases such as superconductivity, [Formula: see text] non-trivial topological states, and electronic nematic states. These can often coexist with intertwined charge-density wave states. Recently, the discovery of the isostructural titanium-based single-crystals, ATi₃Bi₅ (A = K, Rb, Cs), which exhibit similar multiple exotic states but without the concomitant charge-density wave, has opened an opportunity to disentangle these complex states in kagome lattices. Here, we combine high-resolution angle-resolved photoemission spectroscopy and first-principles calculations to investigate the low-lying electronic structure of RbTi₃Bi₅. We demonstrate the coexistence of flat bands and several non-trivial states, including type-II Dirac nodal lines and [Formula: see text] non-trivial topological surface states. Our findings also provide evidence for rotational symmetry breaking in RbTi₃Bi₅, suggesting a directionality to the electronic structure and the possible emergence of pure electronic nematicity in this family of kagome compounds.

Abstract

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