Inhomogeneous superconductivity in organic conductors: role of disorder and magnetic field

TL;DR

This paper models the inhomogeneous superconductivity in organic conductors, emphasizing the effects of disorder and magnetic fields, and demonstrates quantitative agreement with experimental data.

Contribution

It introduces a time-dependent Ginzburg-Landau model considering textured disorder to explain $T_c$ suppression and fluctuation effects on $H_{c2}$ in organic superconductors.

Findings

Calculated $T_c$ matches experimental observations.

Superconducting fluctuations can significantly enhance $H_{c2}$.

Disorder-induced inhomogeneity affects superconducting properties.

Abstract

Several experimental studies have shown the presence of spatially inhomogeneous phase coexistence of superconducting and non superconducting domains in low dimensional organic superconductors. The superconducting properties of these systems are found to be strongly dependent on the amount of disorder introduced in the sample regardless of its origin. The suppression of the superconducting transition temperature $T_c$ shows clear discrepancy with the result expected from the Abrikosov-Gor'kov law giving the behavior of $T_c$ with impurities. Based on the time dependent Ginzburg-Landau theory, we derive a model to account for the striking feature of $T_c$ in organic superconductors for different types of disorder by considering the segregated texture of the system. We show that the calculated $T_c$ quantitatively agrees with experiments. We also focus on the role of superconducting fluctuations on the upper critical fields $H_{c2}$ of layered superconductors showing slab structure where superconducting domains are sandwiched by non-superconducting regions. We found that $H_{c2}$ may be strongly enhanced by such fluctuations.