Charge instability of topological Fermi arcs in chiral crystal CoSi

Zhicheng Rao; Quanxin Hu; Shangjie Tian; Qing Qu; Congrun Chen; Shunye Gao; Zhenyu Yuan; Cenyao Tang; Wenhui Fan; Jierui Huang; Yaobo Huang; Li Wang; Lu Zhang; Fangsen Li; Kedong Wang; Huaixin Yang; Hongming Weng; Tian Qian; Jinpeng Xu; Kun Jiang; Hechang Lei; Yu-Jie Sun; Hong Ding

doi:10.1016/j.scib.2023.01.001

Charge instability of topological Fermi arcs in chiral crystal CoSi

Sci Bull (Beijing). 2023 Jan 30;68(2):165-172. doi: 10.1016/j.scib.2023.01.001. Epub 2023 Jan 5.

Authors

Zhicheng Rao¹, Quanxin Hu², Shangjie Tian³, Qing Qu⁴, Congrun Chen⁴, Shunye Gao², Zhenyu Yuan², Cenyao Tang², Wenhui Fan², Jierui Huang², Yaobo Huang⁵, Li Wang⁶, Lu Zhang², Fangsen Li⁶, Kedong Wang⁴, Huaixin Yang⁷, Hongming Weng⁷, Tian Qian⁷, Jinpeng Xu⁸, Kun Jiang², Hechang Lei⁹, Yu-Jie Sun¹⁰, Hong Ding¹¹

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
² Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
³ School of Materials Science and Engineering, Anhui University, Hefei 230601, China; Laboratory for Neutron Scattering, and Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
⁴ Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
⁵ Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China.
⁶ Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China.
⁷ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Songshan Lake Materials Laboratory, Dongguan 523808, China.
⁸ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China. Electronic address: xujp@iphy.ac.cn.
⁹ Laboratory for Neutron Scattering, and Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Department of Physics, Renmin University of China, Beijing 100872, China. Electronic address: hlei@ruc.edu.cn.
¹⁰ Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: sunyj@sustech.edu.cn.
¹¹ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.

PMID: 36653217
DOI: 10.1016/j.scib.2023.01.001

Abstract

Topological boundary states emerged at the spatial boundary between topological non-trivial and trivial phases, are usually gapless, or commonly referred as metallic states. For example, the surface state of a topological insulator is a gapless Dirac state. These metallic topological boundary states are typically well described by non-interacting fermions. However, the behavior of topological boundary states with significant electron-electron interactions, which could turn the gapless boundary states into gapped ordered states, e.g., density wave states or superconducting states, is of great interest theoretically, but is still lacking evidence experimentally. Here, we report the observation of incommensurable charge density wave (CDW) formed on the topological boundary states driven by the electron-electron interactions on the (001) surface of CoSi. The wavevector of CDW varies as the temperature changes, which coincides with the evolution of topological surface Fermi arcs with temperature. The orientation of the CDW phase is determined by the chirality of the Fermi arcs, which indicates a direct association between CDW and Fermi arcs. Our finding will stimulate the search of more interactions-driven ordered states, such as superconductivity and magnetism, on the boundaries of topological materials.

Keywords: Charge density wave; Chiral crystal; Fermi arcs; Many-body effect; Topological boundary states.