Unconventional chiral charge order in kagome superconductor KV3Sb5

• Published in: Nature materials Vol. 20; no. 10; pp. 1353 - 1357
• Main Authors: 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
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-10-2021; Nature Publishing Group; Springer Nature - Nature Publishing Group
• Subjects: 639/301/119/2792/4128; 639/301/119/2794; 639/766/119/995; Anisotropy; Biomaterials; Charge density waves; Chemistry and Materials Science; Condensed Matter Physics; electronic materials; electronic properties; Energy gap; Hall effect; High temperature; Kagome lattice; Letter; Magnetic fields; Magnetism; MATERIALS SCIENCE; Microscopy; Nanotechnology; Optical and Electronic Materials; quantum hall; Scanning tunneling microscopy; Superlattices; Theoretical analysis; topological insulators; Topology; Unconventional superconductivity
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-021-01034-y

Intertwining quantum order and non-trivial topology is at the frontier of condensed matter physics
1
–
4
. A charge-density-wave-like order with orbital currents has been proposed for achieving the quantum anomalous Hall effect
5
,
6
in topological materials and for the hidden phase in cuprate high-temperature superconductors
7
,
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, KV
3
Sb
5
, 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.
An unconventional chiral charge order is observed in a kagome superconductor by scanning tunnelling microscopy. This charge order has unusual magnetic tunability and intertwines with electronic topology.