Sr2RuO4: an electronic analogue of3He?

Abstract
Sr2RuO4 is a superconductor with a similar structure to a high-Tc cuprate superconductor. Nevertheless, the superconducting state may have different symmetry than that of cuprate superconductors. Strong Hund's rule coupling favours triplet over singlet pairing, similar to 3He. A strong candidate is the odd-parity pairing state which is the two-dimensional analogue of the Balian-Werthamer state of 3He. Various experimental consequences and tests are analysed.