Muon spin relaxation study of the layered kagome superconductor CsV3Sb5

The Z2 topological metals RV3Sb5 (R = K, Rb, Cs) with a layered kagome structure provide a unique opportunity to investigate the interplay between charge order, superconductivity, and topology. Here, we report muon-spin relaxation/rotation (μSR) measurements performed on CsV3Sb5 across a broad temperature range, in order to uncover the nature of the charge density wave order and superconductivity in this material. From zero-field μSR, we find that spontaneous magnetic fields appear below 50 K, which is well below the charge density wave transition (T∗∼93 K). We show that these spontaneous fields are dynamic in nature making it difficult to associate them with a hidden static order. The superconducting state of CsV3Sb5 is found to preserve time-reversal symmetry, and the transverse-field μSR results are consistent with a superconducting state that has two fully open gaps.