Abstract
This review presents a summary and evaluation of the experimental
properties of unconventional superconductivity in Sr2RuO4 as they were
known in the spring of 2002. At the same time, the paper is intended to
be useful as an introduction to the physics of spin-triplet
superconductivity. First, the authors show how the normal-state
properties of Sr2RuO4 are quantitatively described in terms of a
quasi-two-dimensional Fermi liquid. Then they summarize its
phenomenological superconducting parameters in the framework of the
Ginzburg-Landau model, and discuss the existing evidence for
spin-triplet pairing. After a brief introduction to the vector order
parameter, they examine the most likely symmetry of the triplet state.
The structure of the superconducting energy gap is discussed, as is the
effect of symmetry-breaking magnetic fields on the phase diagram. The
article concludes with a discussion of some outstanding issues and
desirable future work. Appendixes on additional details of the normal
state, difficulty in observing the bulk Fermi surface by angle-resolved
photoemission, and the enhancement of superconducting transition
temperature in a two-phase Sr2RuO4-Ru system are included.
