Properties of spin-triplet, even-parity superconductors

The physical consequences of the spin-triplet, even-parity pairing that has been predicted to exist in disordered two-dimensional electron systems are considered in detail. We show that the presence of an attractive interacti on in the particle-particle spin-triplet channel leads to an instability of the normal metal that competes with the localizing effects of the disorder . The instability is characterized by a diverging length scale, and has all of the characteristics of a continuous phase transition. The transition an d the properties of the ordered phase are studied in mean-field theory, and by taking into account Gaussian fluctuations. We find that the ordered pha se is indeed a superconductor with an ordinary Meissner effect and a free e nergy that is lower than that of the normal metal. Various technical points that have given rise to confusion in connection with this and other manife stations of odd-gap superconductivity are also discussed. [S0163-1829(99)13 329-0].