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Charge ordered kagome lattices have been demonstrated to be intriguing platforms for studying the intertwining of topology, correlation, superconductivity and magnetism [1-4]. The recently discovered charge ordered kagome material ScV₆Sn₆ [5] does not feature a magnetic groundstate or excitations, thus it is often regarded as a conventional paramagnet. In this talk, I will present the results of muon-spin rotation and magnetotransport experiments, uncovering an unexpected hidden magnetism of the charge order [6]. We observe a striking enhancement of the internal field width sensed by the muon ensemble, which takes place within the charge ordered state. More remarkably, the muon spin relaxation rate below the charge ordering temperature is substantially enhanced by applying an external magnetic field. Taken together with the hidden magnetism found in AV₃Sb₅ (A = K, Rb, Cs) [1-3] and FeGe [4] kagome systems, our results suggest ubiqitous time-reversal symmetry-breaking in charge ordered kagome lattices. This is substantiated by our very recent discovery of above room-temperature charge order and its magnetic response in a prototypical kagome superconductor LaRu₃Si₂ [7].

[1] B. Ortiz, et al. Phys. Rev. Lett. 125, 247002 (2020).

[2] C. Mielke III, D. Das, et al. and Z. Guguchia. Nature 602, 245-250 (2022).

[3] Z. Guguchia et al. Nature Communications 14, 153 (2023).

[4] J.-X. Yin et al. Phys. Rev. Lett. 129, 166401 (2022). 

[5] H.W.S. Arachchige, et al. Phys. Rev. Lett. 129, 216402 (2022).

[6] Z. Guguchia et al. arXiv:2304.06436v1 (2023). 

[7] I. Plokhikh, et al. and Z. Guguchia. arXiv:2309.09255 (2023).