Electron-electron relaxation in two-dimensional impure superconductors

The electron-electron relaxation in impure two-dimensional superconductors is studied. All channels of the electron-electron interaction classified in the Nambu representation are taken into account. It is shown that the reco mbination relaxation rate originates from quasiparticle processes associate d with fluctuations of the electron density and the phase of the order para meter. At low temperatures the recombination relaxation rate has a double e xponential temperature dependence. The scattering relaxation rate at low te mperatures has a power-law temperature dependence due to contributions from gapless collective excitations, the phase modes. The two-layer superconduc tor-normal-metal system is also considered. It is shown that the recombinat ion relaxation rate in the superconducting layer has a single exponential f actor at low temperatures in comparison with a one layer superconducting sy stem. This increase in the recombination relaxation rate originates from th e interlayer Coulomb interaction and may be used in the constructing of sup erconducting radiation detectors.