First-principles-based $\pm s$-wave modelling for iron-based superconductors:Studies for specific heat and nuclear magnetic relaxation rate

TL;DR

This paper develops a first-principles multi-band $ ext{±}s$-wave model for iron-based superconductors, successfully explaining diverse experimental results on superconducting states by incorporating small gaps and material-specific features.

Contribution

It introduces a realistic multi-band $ ext{±}s$-wave pairing model that overcomes limitations of simplified models, explaining experimental controversies in iron-based superconductors.

Findings

Model explains experimental discrepancies in superconducting states.

Small gaps lead to material-dependent behaviors.

Successfully resolves issues that simplified models could not address.

Abstract

In order to consistently explain controversial experimental results on superconducting states observed by different probes in typical iron-based superconductors, we construct a realistic multi-band $\pm s$-wave pairing model by combining the quasiclassical formalism with the first-principles calculation. The model successfully resolves the controversies in contrast to the fact that simplified models such as two-band $\pm s$-wave one fail to do. A key in the model is the existence of relatively small gaps which leads to material-dependent peculiarities.