Probing the anomalous symmetry-breaking in kagome material CsV3Sb5 via third-order nonlinearity

Abstract

The kagome material has rapidly established itself as a research frontier in condensed matter physics, owing to its distinctive geometric structure and the rich array of unconventional physical phenomena. In the kagome AV3Sb5 (A = K, Rb, Cs) family, the charge-ordered state exhibits a remarkable characteristic, i.e., anomalous symmetry-breaking, which is tied to the topological nature of the electronic band structure. Here, we report the third-order nonlinear longitudinal and Hall responses that persist stably up to room temperature in the kagome material CsV3Sb5. Notably, the nonlinear responses demonstrate significant enhancement below the charge density wave (~ 77 K) order and anomalous symmetry-breaking (~ 39 K) state. The scaling analysis indicates that the third-order nonlinear transport is governed jointly by quantum geometric contribution and extrinsic scattering. This study realizes a giant third-order nonlinear response and provides a distinct method to detect anomalous symmetry-breaking in CsV3Sb5.