Three-state nematicity and magneto-optical Kerr effect in the charge density waves in kagome superconductors
By Yishuai Xu, Z. Ni, Yizhou Liu, B. Ortiz, S. Wilson, Binghai Yan, L. Balents, Liang Wu. Nature Physics, 2022
240 citations recorded by the source corpus.
The kagome lattice provides a fascinating playground to study geometrical frustration, topology and strong correlations. The newly discovered kagome metals AV3Sb5 (where A can refer to K, Rb or Cs) exhibit phenomena including topological band structure, symmetry-breaking charge-density waves and superconductivity. Nevertheless, the nature of the symmetry breaking in the charge-density wave phase is not yet clear, despite the fact that it is crucial in order to understand whether the superconductivity is unconventional. In this work, we perform scanning birefringence microscopy on all three members of this family and find that six-fold rotation symmetry is broken at the onset of the charge-density wave transition in all these compounds. We show that the three nematic domains are oriented at 120° to each other and propose that staggered charge-density wave orders with a relative π phase shift between layers is a possibility that can explain these observations. We also perform magneto-optical Kerr effect and circular dichroism measurements. The onset of both signals is at the transition temperature, indicating broken time-reversal symmetry and the existence of the long-sought loop currents in that phase. The interplay between superconductivity that might break time-reversal symmetry and charge order is a key issue in kagome materials. Now, optical measurements show that spatial and time-reversal symmetries are broken at the onset of charge order.
Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics
View Paper: https://www.semanticscholar.org/paper/45c7884d7b13bf2f55ff722bffd6ff3539345879
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In Atomic and Molecular Physics, and Optics
Citations in the corpus
- Quantum states and intertwining phases in kagome materials (2023, background): “…TRSB. Signals of the zero-field Kerr effect and circular dichroism are detected concomitant with the CDW transition 130,131,180 , and nematic domains (of size ~100 µm) with opposite signs are detected without applying external magnetic field 130,180 ; the domains are magnetic-field-tunable 180 .”