Impurity Bound States and Symmetry of the Superconducting Order Parameter in Sr2RuO4

Recent experiments on Sr2RuO4 have indicated the presence of linear nodes in the superconducting order parameter. Among the possible spin triplet states, 2D p-wave superconductivity with Eu symmetry appears to be inconsistent with the experiments, whereas the 2D f-wave order parameter with B1g × Eu symmetry turns out to be a more likely candidate. Here it is shown how the quasi-particle bound state wave functions around a single impurity provide a clear signature of the symmetry of the underlying superconducting order parameter. Typeset using REVTEX 1