Electron-electron relaxation in two-dimensional and layered superconductors

The electron-electron relaxation in two-dimensional and layered superconductors is studied. The calculations go beyond the random-phase approximation in the lowest order of perturbation theory for any relation between the screening momentum kappa and the Fermi momentum P-F. Besides the Coulomb electron-electron interaction we also include all possible channels of the electron-electron interaction in a superconductor. We show that the electron relaxation rate in the superconducting state acquires the logarithmic factor similar to the normal state. The electron relaxation drastically changes in two-dimensional d-wave superconductors in comparison with the three-dimensional case. We also show that in a superconductor-normal-metal system the recombination relaxation rate in the superconducting layer in the low-temperature region strongly increased (by the exponential factor), what may be important for superconducting radiation detectors.