Unconventional chiral charge order in kagome superconductor KV3Sb5

Yu-Xiao Jiang; Jia-Xin Yin; M Michael Denner; Nana Shumiya; Brenden R Ortiz; Gang Xu; Zurab Guguchia; Junyi He; Md Shafayat Hossain; Xiaoxiong Liu; Jacob Ruff; Linus Kautzsch; Songtian S Zhang; Guoqing Chang; Ilya Belopolski; Qi Zhang; Tyler A Cochran; Daniel Multer; Maksim Litskevich; Zi-Jia Cheng; Xian P Yang; Ziqiang Wang; Ronny Thomale; Titus Neupert; Stephen D Wilson; M Zahid Hasan

doi:10.1038/s41563-021-01034-y

Unconventional chiral charge order in kagome superconductor KV₃Sb₅

Nat Mater. 2021 Oct;20(10):1353-1357. doi: 10.1038/s41563-021-01034-y. Epub 2021 Jun 10.

Authors

Yu-Xiao Jiang^#¹, Jia-Xin Yin^#², M Michael Denner^#³, Nana Shumiya^#¹, Brenden R Ortiz^#⁴, Gang Xu^#⁵, Zurab Guguchia⁶, Junyi He⁵, Md Shafayat Hossain¹, Xiaoxiong Liu³, Jacob Ruff⁷, Linus Kautzsch⁷, Songtian S Zhang¹, Guoqing Chang⁸, Ilya Belopolski¹, Qi Zhang¹, Tyler A Cochran¹, Daniel Multer¹, Maksim Litskevich¹, Zi-Jia Cheng¹, Xian P Yang¹, Ziqiang Wang⁹, Ronny Thomale¹⁰, Titus Neupert³, Stephen D Wilson⁴, M Zahid Hasan^{11

12

13

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Affiliations

¹ Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
² Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA. jiaxiny@princeton.edu.
³ Department of Physics, University of Zurich, Zurich, Switzerland.
⁴ Materials Department and California Nanosystems Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
⁵ Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China.
⁶ Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Villigen, Switzerland.
⁷ Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, USA.
⁸ Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
⁹ Department of Physics, Boston College, Chestnut Hill, MA, USA.
¹⁰ Institut für Theoretische Physik und Astrophysik, Julius-Maximilians-Universität Würzburg, Würzburg, Germany.
¹¹ Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA. mzhasan@princeton.edu.
¹² Lawrence Berkeley National Laboratory, Berkeley, CA, USA. mzhasan@princeton.edu.
¹³ Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, NJ, USA. mzhasan@princeton.edu.
¹⁴ Quantum Science Center, Oak Ridge, TN, USA. mzhasan@princeton.edu.

^# Contributed equally.

PMID: 34112979
DOI: 10.1038/s41563-021-01034-y

Abstract

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, 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.