We have studied the Josephson coupling between a conventional s-wave superconductor (In) and Sr2RuO4 and found that the coupling is allowed in the in-plane direction, but not along the c axis. This selection rule indicates that the symmetry of superconducting order parameter of Sr2RuO4 is either p- or alternatively, purely d-wave. If Sr2RuO4 is a p-wave superconductor, as strongly favored by other experimental evidence, our result suggests that the pairing state of Sr2RuO4 is Gamma5 with d(k) = z(kx +/- iky), a nodeless state in which the spins of the superconducting electrons lie in the RuO2 planes.
Cite
@article{arxiv.cond-mat/9909214,
title = {Selection Rule in Josephson Coupling between In and Sr2RuO4},
author = {R. Jin and Y. Liu and Z. Q. Mao and Y. Maeno},
journal= {arXiv preprint arXiv:cond-mat/9909214},
year = {2007}
}