The role of spin-orbit coupling for the superconducting state in Sr2RuO4

The odd-parity spin-triplet Cooper pairing states show a six-fold degeneracy for a quasi-two-dimensional electron system. In this article we show how spin-orbit coupling can lift this degeneracy for Sr2RuO4 taking the band structure based on the three relevant t2g-orbitals of the Ru-ions into account. The stabilized state depends on the relative strength of the pairing interaction. We show that under reasonable assumptions the chiral pairing state d(k) = z(kx ± iky) is favored against the others. (orig.)