Superconductivity of a hexagonal noncentrosymmetric superconductor

Superconductors (SC) where the crystal lattice lacks inversion symmetry may have Cooper pairs which are a mixture of singlet and triplet states, but the conditions giving rise to this unusual pairing are not well understood. Several of these SC also have broken time-reversal-symmetry (TRS) below the transition, the origin of which is not determined. We aim to use muon-spin relaxation/rotation to characterize a hexagonal SC without inversion symmetry LaRhSn, to search for broken TRS, and to measure the penetration depth in order to determine the superconducting gap structure. Whether or not TRS is broken will enable the testing of competing theoretical proposals, whereas knowledge of the gap structure provides information about whether there is singlet-triplet mixing.