Ab-initio theory of Iron based superconductors

TL;DR

This paper presents a first-principles study of Fe-based superconductors, revealing that antiferromagnetic paramagnons drive superconductivity in FeSe, resulting in a modulated s± gap symmetry, with implications for understanding high-temperature superconductivity.

Contribution

It introduces a comprehensive ab-initio approach that simultaneously considers phonon, charge, and spin-fluctuation effects in Fe-based superconductors, highlighting the dominant role of magnetic fluctuations in FeSe.

Findings

Antiferromagnetic paramagnons are the primary pairing mechanism in FeSe.

Superconducting gap symmetry in FeSe is modulated s±.

Phonons and charge fluctuations are less influential than magnetic fluctuations.

Abstract

We report the first-principles study of superconducting critical temperature and superconducting properties of Fe-based superconductors taking into account on the same footing phonon, charge and spin-fluctuation mediated Cooper pairing. We show that in FeSe this leads to a modulated s$\pm$ gap symmetry, and that the antiferromagnetic paramagnons are the leading mechanism for superconductivity in FeSe, overcoming the strong repulsive effect of both phonons and charge pairing.