Large $D-2$ Theory of Superconducting Fluctuations in a Magnetic Field and its Application to Iron-Pnictides

TL;DR

This paper develops a large D-2 theoretical framework for layered superconductors in magnetic fields, capturing interlayer effects and phase transitions, and applies it to interpret experimental data on iron-pnictides.

Contribution

It introduces a self-consistent large D-2 theory incorporating interlayer coupling in layered superconductors, revealing two phase transitions and providing explicit fluctuation property expressions.

Findings

Identifies vortex liquid-to-solid and Bose-Einstein condensation transitions.

Derives explicit formulas for magnetization, specific heat, and conductivity.

Matches theoretical predictions with experimental data on iron-pnictide superconductors.

Abstract

A Ginzburg-Landau approach to fluctuations of a layered superconductor in a magnetic field is used to show that the interlayer coupling can be incorporated within an interacting self-consistent theory of a single layer, in the limit of a large number of neighboring layers. The theory exhibits two phase transitions -- a vortex liquid-to-solid transition is followed by a Bose-Einstein condensation into the Abrikosov lattice -- illustrating the essential role of interlayer coupling. Using this theory, explicit expressions for magnetization, specific heat, and fluctuation conductivity are derived. We compare our results with recent experimental data on the iron-pnictide superconductors.