Synergy between Hund-driven correlations and boson-mediated Superconductivity

TL;DR

This paper investigates how Hund-driven correlations enhance superconductivity in multiorbital systems, especially iron-based superconductors, by analyzing the interplay of electronic correlations and bosonic mechanisms.

Contribution

It demonstrates that Hund's coupling significantly promotes superconductivity and enhances orbital-selective gaps compared to ordinary correlated metals.

Findings

Superconductivity persists more in Hund's metals than in ordinary correlated metals.

Spectral weight redistribution in Hund's metals enhances orbital-selective superconducting gaps.

Results align with experimental observations in iron-based superconductors.

Abstract

Multiorbital systems such as the iron-based superconductors provide a new avenue to attack the longstanding problem of superconductivity in strongly correlated systems. In this work we study the superconductivity driven by a generic bosonic mechanism in a multiorbital model including the full dynamical electronic correlations induced by the Hubbard U and the Hund's coupling. We show that superconductivity survives much more in a Hund's metal than in an ordinary correlated metal with the same degree of correlation. The crucial role of the redistribution of spectral weight in the Hund's metal reflects also in the enhancement of the orbital-selective character of the superconducting gaps, in agreement with experiments in iron-based superconductors.