Magnetoconductance of thin-film superconductors near critical disorder

Gauge-invariant approximations are used to derive all diagrams for the current response function to lowest order in the superconducting pair fluctuations. The resulting expression for the magnetoconductance extends the range in temperature and magnetic field over which meaningful comparisons with experimental data can be made. This aspect of the theory is illustrated in an analysis of magnetoconductance data on 100-Å-thick In/${\mathrm{InO}}_{\mathrm{x}}$ superconductors near critical disorder where the transition temperature is rapidly suppressed with increasing sheet resistance. The temperature dependence and magnitude of the derived inelastic scattering rate is in good agreement with theory which includes the effect of superconducting fluctuations on the two-dimensional inelastic electron-electron scattering rate.