Coexisting Multiple Charge Orders and Magnetism in the Kagome Superconductor LaRuSi.

The Kagome lattice has emerged as a promising platform for hosting unconventional chiral charge orders at high temperatures. In the context of the correlated Kagome superconductor LaRuSi, a room-temperature charge-ordered state with a propagation vector of ( , 0, 0) is previously reported. However, understanding the interplay between this charge order and superconductivity, particularly with respect to time-reversal-symmetry breaking, remains elusive. In this study, we employ single-crystal X-ray diffraction, magnetotransport measurements, muon-spin rotation experiments, and first-principles calculations to investigate charge order and its electronic and magnetic responses in LaRuSi across a wide temperature range, down to the superconducting state. These findings reveal the appearance of a charge order with a propagation vector of ( , 0, 0) below T ≃ 80 K, which coexists with the previously identified room temperature primary charge order ( , 0, 0). The primary charge-ordered state exhibits zero magnetoresistance. In contrast, the appearance of the secondary charge order at T is accompanied by a notable magnetoresistance response and a pronounced temperature-dependent Hall effect, which experiences a sign reversal, switching from positive to negative below T* ≃ 35 K. Intriguingly, a significant enhancement is observed in the internal field width sensed by the muon ensemble below T* ≃ 35 K. Moreover, the muon spin relaxation rate exhibits a substantial increase upon the application of an external magnetic field below T ≃ 80 K. These results highlight the coexistence of two distinct types of charge order and magnetism in LaRuSi within the correlated Kagome lattice, along with superconductivity. This study sheds light on the intricate electronic and magnetic phenomena occurring in Kagome superconductors, providing valuable insights into their unique properties and potential applications.