- Jiang, Yu-Xiao;
- Yin, Jia-Xin;
- Denner, M Michael;
- Shumiya, Nana;
- Ortiz, Brenden R;
- Xu, Gang;
- Guguchia, Zurab;
- He, Junyi;
- Hossain, Md Shafayat;
- Liu, Xiaoxiong;
- Ruff, Jacob;
- Kautzsch, Linus;
- Zhang, Songtian S;
- Chang, Guoqing;
- Belopolski, Ilya;
- Zhang, Qi;
- Cochran, Tyler A;
- Multer, Daniel;
- Litskevich, Maksim;
- Cheng, Zi-Jia;
- Yang, Xian P;
- Wang, Ziqiang;
- Thomale, Ronny;
- Neupert, Titus;
- Wilson, Stephen D;
- Hasan, M Zahid
Intertwining quantum order and non-trivial topology is at the frontier of condensed matter physics1-4. A charge-density-wave-like order with orbital currents has been proposed for achieving the quantum anomalous Hall effect5,6 in topological materials and for the hidden phase in cuprate high-temperature superconductors7,8. However, the experimental realization of such an order is challenging. Here we use high-resolution scanning tunnelling microscopy to discover an unconventional chiral charge order in a kagome material, KV3Sb5, with both a topological band structure and a superconducting ground state. Through both topography and spectroscopic imaging, we observe a robust 2 × 2 superlattice. Spectroscopically, an energy gap opens at the Fermi level, across which the 2 × 2 charge modulation exhibits an intensity reversal in real space, signalling charge ordering. At the impurity-pinning-free region, the strength of intrinsic charge modulations further exhibits chiral anisotropy with unusual magnetic field response. Theoretical analysis of our experiments suggests a tantalizing unconventional chiral charge density wave in the frustrated kagome lattice, which can not only lead to a large anomalous Hall effect with orbital magnetism, but also be a precursor of unconventional superconductivity.