Electronic nature of chiral charge order in the kagome superconductor Cs V3Sb5

Zhiwei Wang, Yu Xiao Jiang, Jia Xin Yin, Yongkai Li, Guan Yong Wang, Hai Li Huang, Shen Shao, Jinjin Liu, Peng Zhu, Nana Shumiya, Md Shafayat Hossain, Hongxiong Liu, Youguo Shi, Junxi Duan, Xiang Li, Guoqing Chang, Pengcheng Dai, Zijin Ye, Gang Xu, Yanchao WangHao Zheng, Jinfeng Jia, M. Zahid Hasan, Yugui Yao

Research output: Contribution to journalArticlepeer-review

125 Citations (Scopus)

Abstract

Kagome superconductors with TC up to 7 K have been discovered for over 40 y. Recently, unconventional chiral charge order has been reported in kagome superconductor KV3Sb5, with an ordering temperature of one order of magnitude higher than the TC. However, the chirality of the charge order has not been reported in the cousin kagome superconductor CsV3Sb5, and the electronic nature of the chirality remains elusive. In this paper, we report the observation of electronic chiral charge order in CsV3Sb5 via scanning tunneling microscopy (STM). We observe a 2 × 2 charge modulation and a 1 × 4 superlattice in both topographic data and tunneling spectroscopy. 2 × 2 charge modulation is highly anticipated as a charge order by fundamental kagome lattice models at van Hove filling, and is shown to exhibit intrinsic chirality. We find that the 1 × 4 superlattices form various small domain walls, and can be a surface effect as supported by our first-principles calculations. Crucially, we find that the amplitude of the energy gap opened by the charge order exhibits real-space modulations, and features 2 × 2 wave vectors with chirality, highlighting the electronic nature of the chiral charge order. STM study at 0.4 K reveals a superconducting energy gap with a gap size 2Δ=0.85meV, which estimates a moderate superconductivity coupling strength with 2Δ/kBTC=3.9. When further applying a c-axis magnetic field, vortex core bound states are observed within this gap, indicative of clean-limit superconductivity.

Original languageEnglish
Article number075148
JournalPhysical Review B
Volume104
Issue number7
DOIs
Publication statusPublished - 15 Aug 2021

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