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The recently discovered kagome metal CsV3Sb5 has attracted enormous attention due to its nontrivial topological electronic structure and intertwined symmetry-broken states [1,2]. One central question is the nature of the broken symmetry associated with the charge density wave (CDW) onsets at T ~ 90K [3,4]. In this talk, I will present the measurement of elastoresistivity and elastocaloric effect of CsV3Sb5. Using three different techniques, the differential, the modified Montgomery, and the transverse method, we precisely decomposed the elastoresistivity coefficient into different symmetry channels. We found that the isotropic elastoresistivity coefficient (i.e., m11+m12) increases substantially below the charge density wave transition temperature and becomes several times larger than the nearly temperature-independent anisotropic coefficient (i.e., m11-m12). Our results suggest that the charge density wave phase in CsV3Sb5 either does not break rotational symmetry or its broken rotational symmetry is decoupled from the anisotropic strain.

Reference:

[1] B. R. Ortiz et al., New Kagome Prototype Materials: Discovery of KV3Sb5, RbV3Sb5, and CsV3Sb5, Physical Review Materials 3, 94407 (2019).

[2] S. Y. Yang et al., Giant, Unconventional Anomalous Hall Effect in the Metallic Frustrated Magnet Candidate, KV3Sb5, Science Advances 6, 1 (2020).

[3] L. Nie et al., Charge-Density-Wave-Driven Electronic Nematicity in a Kagome Superconductor, Nature 604, 7904 (2022).

[4] Y. Xu, Z. Ni, Y. Liu, B. R. Ortiz, S. D. Wilson, B. Yan, L. Balents, and L. Wu, Universal Three-State Nematicity and Magneto-Optical Kerr Effect in the Charge Density Waves in AV3Sb5 (A=Cs, Rb, K), 5, 1 (2022).