Even-parity spin-triplet superconductivity in disordered electronic systems

A purely electronic mechanism for superconductivity in disordered Fermi systems is given. It is based on long-time-tail effects in electronic correlations, is strongest in two-dimensional systems, and leads to spin-triplet even-parity pairing. Estimates are given for the mean-field transition temperature to the superconducting state. The superconducting state is discussed in detail. In particular, the superconducting gap function, the tunneling density of states in the superconducting phase, and the low-temperature specific heat are computed. We compare and contrast these results with those for conventional superconductors. We also discuss which classes of materials might provide an experimental realization of the superconducting state discussed here.