Evidence of nodal gap structure in the noncentrosymmetric superconductor Y2C3

The symmetries of a superconductor, e.g., time-reversaland spatial inversion symmetries, may impose importantconstraints on the pairing states. Among the previouslyinvestigatedsuperconductors,mostpossessaninversioncenterin their crystal structures, in which the Cooper pairs areeither in an even-parity spin-singlet or odd-parity spin-tripletpairing state, according to the Pauli principle and parityconservation.