1. Time-reversal symmetry breaking in charge density wave of CsV$_3$Sb$_5$ detected by polar Kerr effect
- Author
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Hu, Yajian, Yamane, Soichiro, Mattoni, Giordano, Yada, Kanae, Obata, Keito, Li, Yongkai, Yao, Yugui, Wang, Zhiwei, Wang, Jingyuan, Farhang, Camron, Xia, Jing, Maeno, Yoshiteru, and Yonezawa, Shingo
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
The Kagome lattice exhibits rich quantum phenomena owing to its unique geometric properties. Appealing realizations are the Kagome metals AV$_3$Sb$_5$ (A = K, Rb, Cs), where unconventional charge density wave (CDW) is intertwined with superconductivity and non-trivial band topology. Several experiments suggest that this CDW is a rare occurrence of chiral CDW characterized by orbital loop current. However, key evidences of loop current, spontaneous time-reversal symmetry-breaking (TRSB) and the coupling of its order parameter with the magnetic field remain elusive. Here, we investigate the CDW in CsV3Sb5 by magneto-optic polar Kerr effect with sub-microradian resolution. Under magnetic field, we observed a jump of the Kerr angle at the CDW transition. This jump is magnetic-field switchable and scales with field, indicating magneto--chirality coupling related to non-trivial band topology. At zero field, we found non-zero and field-trainable Kerr angle below CDW transition temperature, signaling spontaneous TRSB. Our results provide a crucial step to unveil quantum phenomena in correlated Kagome materials.
- Published
- 2022