Symmetry properties of the nodal superconductor PrOs4Sb12

We present a theoretical study of the superconducting gap function in PrOs4Sb12 using a symmetry-based approach. A three-component order parameter in the triplet channel best describes superconductivity. The gap function is nondegenerate and the lower branch has four cusp nodes at unusual points of the Fermi surface, which lead to power law behaviors in the density of states, specific heat, and nuclear spin relaxation rate.