期刊

Science Bulletin

标题

Charge instability of topological Fermi arcs in chiral crystal CoSi

作者

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

摘要

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 (0 0 1) 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.

原文链接

https://www.sciencedirect.com/science/article/pii/S2095927323000063