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Quantum corrections to the resistance in two-dimensional disordered superconductors above<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>: Al, Sn, and amorphous<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Bi</mml:mi></mml:mrow><mml:mrow><mml:mn>0.9</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Tl</mml:mi></mml:mrow><mml:mrow><mml:mn>0.1</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>films

Gerd BergmannInstitut für Festkörperforschung der Kernforschungsanlage Jülich, Postfach 1913, D-5170 Jülich, West Germany
1984lv
ABI

Abstract

Disordered films of superconductors above their transition temperature ${T}_{c}$ show several quantum corrections to the conductance, weak localization (WL), two contributions from the retarded Coulomb interaction, and two contributions from superconducting fluctuations, the Aslamazov-Larkin (AL) and the Maki-Thompson (MT) terms. In a magnetic field, most of them show a magnetoresistance and all are temperature dependent. In this paper the temperature and field dependence of the resistance is measured for Al, Sn, and amorphous ${\mathrm{Bi}}_{0.9}$${\mathrm{Tl}}_{0.1}$ films. This covers the weak-coupling and the extremely-strong-coupling superconductors as well. Of particular interest are the AL and the MT terms. The latter can be reduced by a pair-breaking mechanism. This pair breaking is caused by the inelastic-scattering time of the conduction electrons and can be measured by weak localization. Al has only a small spin-orbit scattering but by covering it with \textonequarter{} atomic layer of Au it can be transformed into a strong spin-orbit scatterer. This allows an independent determination of the inelastic lifetime ${\ensuremath{\tau}}_{i}$ and spin-orbit scattering time ${\ensuremath{\tau}}_{\mathrm{s}.\mathrm{o}.}$ and therefore a complete examination of the theory and its consistency. The agreement between experiment and theory is very good for the magnetoresistance. However, the theory for the temperature dependence of the resistance fails (with the exception of the contribution of WL). For the intermediate- and strong-coupling superconductors the applicability of the existing theories is restricted. The magnetoresistance of amorphous ${\mathrm{Bi}}_{0.9}$${\mathrm{Tl}}_{0.1}$ is essentially determined by the AL contribution.

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