Triplet pairing, orbital selectivity and correlations in Iron-based superconductors

TL;DR

This paper investigates how strong Coulomb interactions and Hund's coupling influence orbital selectivity and pairing mechanisms in Iron-based superconductors, highlighting the role of $xy$ orbital localization in superconductivity.

Contribution

It introduces a slave-boson approach to analyze band renormalization and pair susceptibility, comparing triplet RVB and $s__$ pairing theories in this context.

Findings

Orbital selectivity favors $xy$ orbital localization or delocalization.

Both triplet RVB and $s__$ pairing theories support superconductivity with delocalized $xy$ orbitals.

Strong Coulomb and Hund's interactions significantly influence pairing mechanisms.

Abstract

We use a slave-boson approach to study the band renormalization and pair susceptibility in the normal state of Iron-based superconductors in presence of strong Coulomb repulsion and Hund's interaction. Our results show orbital selectivity toward localization of $xy$ orbitals and its interplay with superconductivity. We also compare the recently proposed triplet resonating valence bond theory of superconductivity in Iron-based superconductors with the more conventional $s_\pm$ pairing and show that both favor a superconductivity when the $xy$ orbital is delocalized.