Quantum contributions to the magnetoconductivity of critically disordered superconducting TiN films.

ABSTRACT

The onset of superconductivity in the presence of disorder is a fundamental problem of condensed matter physics. Here we investigate the magnetoconductance of disordered ([Formula see text]) superconducting TiN films above the critical temperature T c. We show that the magnetoconductivity of moderately disordered films with [Formula see text] is in full agreement with the perturbative theory of quantum contributions to conductivity. We demonstrate that the magnetoconductivity of films with [Formula see text] is also in agreement with the perturbative theory down to temperatures [Formula see text]. The quantitative discrepancy between experiment and theory develops only below temperatures [Formula see text] for films with [Formula see text]. This discrepancy can be eliminated if we assume steeper temperature dependence of the Larkin's electron-electron attraction strength, [Formula see text]. The obtained temperature dependence of electron phase breaking time [Formula see text] is in agreement with theoretical predictions for all samples.