Theory of Magneto-resistance of Disordered Superconducting Films

TL;DR

This paper presents a theoretical model explaining the large magneto-resistance peaks in disordered superconducting films, attributing them to superconducting islands and Coulomb blockade effects, aligning well with experimental observations.

Contribution

The paper introduces a comprehensive model that explains magneto-resistance behavior across all magnetic fields in disordered superconducting films, incorporating superconducting islands and Coulomb blockade effects.

Findings

Model reproduces the large resistance peak observed experimentally.

Coulomb blockade causes negative magneto-resistance at high fields.

Resistance sign change explained by diminishing Coulomb blockade effects.

Abstract

Recent experimental studies of magneto-resistance in disordered superconducting thin films reveal a huge peak (about 5 orders of magnitude). While it may be expected that magnetic field destroys superconductivity, leading to an enhanced resistance, attenuation of the resistance at higher magnetic fields is surprising. We propose a model which accounts for the experimental results in the entire range of magnetic fields, based on the formation of superconducting islands due to fluctuations in the superconducting order parameter amplitude. At strong magnetic fields Coulomb blockade in these islands gives rise to negative magneto-resistance. As the magnetic field is reduced the effect of Coulomb blockade diminishes and eventually the magneto-resistance changes sign. Numerical calculations show good qualitative agreement with experimental data.