Superconductivity in Fe and As based compounds: a bridge between MgB2 and cuprates

TL;DR

This paper explores the superconducting properties of FeAs-based compounds, highlighting their similarities to MgB2 and differences from cuprates, especially regarding lattice effects and gap symmetry, to better understand high-temperature superconductivity.

Contribution

It introduces a lattice-mediated multi-gap superconductivity model for FeAs compounds, linking their behavior to both MgB2 and cuprates, emphasizing polaronic effects and gap symmetry.

Findings

FeAs superconductors resemble MgB2 with lattice effects

Polaronic lattice effects are present in FeAs compounds

The superconducting gaps are isotropic s-wave in FeAs materials

Abstract

By interpreting various experimental data for the new high temperature FeAs type superconductors in terms of lattice mediated multi gap superconductivity, it is shown that these systems strongly resemble MgB2, however, with the distinction that local polaronic lattice effects exist. This fact establishes a connection to cuprate high temperature superconductors where polaron formation is essential for the pseudogap phase and the unconventional isotope effects observed there. However, similar to MgB2 and in contrast to cuprates the two superconducting gaps in the Fe-As based materials are isotropic s-wave gaps.