The novel 2D Kagome AV3Sb5 (A = Cs, Rb, K) compounds [1] offer a perfect playground to study the interplay between competing electronic charge density waves (CDW) and superconducting (SC) instabilities and the role of possible hidden chiral orders. Both CDW and SC are believed to arise from saddle points in the band structures being proximal to the Fermi energy. Van Hove singularities (vHs) arise from V orbitals comprising the Kagomè nets and are believed to support nesting-driven symmetry breaking. Interestingly in these materials no measurable ordered local spin moments have been observed so far. However, they show an anomalous Hall effect and very recent muon spin relaxation measurements [2,3] indicate a possible cascade of time-reversal symmetry breaking evidenced by multiple anomalous increase of the muon depolarization rate when approaching the low temperature regime.Here we show a systematic investigation of undoped, hole doped and electron doped AV3Sb5 (A = Cs, Rb, K) compounds by combining muon spin spectroscopy and nuclear magnetic resonance in both the CDW and SC regime [4-5]. These techniques turn out to be very sensitive probe of the different symmetry breaking phenomena occurring in the 2D Kagomè materials, some of which elude other experimental probes.The experimental results will be complemented by Density Functional Theory calculations to unveil the role of the lattice and the electronic structure played in the observed phenomena. [1] B. R. Ortiz et al., Phys. Rev. Materials 3, 094407 (2019); B. R. Ortiz, et al. Phys. Rev. Lett. 125, 247002 (2020); S.-Y. Yang et al., Sci. Adv. 6, eabb6003 (2020); B. R. Ortiz, et al., Phys. Rev. Mater. 5, 034801 (2021).[2] R. Khasanov et al., Phys. Rev. Res. 4, 023244 (2022); Li Yu et al., Arxiv 2107.10714 (2021)[3] Z. Guguchia et al. Nature Comm. 14, 153 (2023)[4] J. Frassineti et al., Phys. Rev. Research 5 (2023) L012017[5] Y. M. Oey et al., Phys. Rev. Materials 6 (2022), L041801[6] J. Frassineti et al., in preparation.
