Synergy between Hund-Driven Correlations and Boson-Mediated Superconductivity.

Area of Science:

• Condensed matter physics
• Materials science
• Quantum mechanics

Background:

• Superconductivity in strongly correlated systems remains a significant challenge.
• Multiorbital systems, particularly iron-based superconductors, offer novel platforms for studying superconductivity.
• Understanding the role of electronic correlations is crucial for advancing superconductivity theory.

Purpose of the Study:

• To investigate superconductivity in a multiorbital model with dynamical electronic correlations.
• To explore the impact of Hubbard U and Hund's coupling on superconductivity.
• To compare superconductivity in a Hund's metal versus an ordinary correlated metal.

Main Methods:

• Utilized a multiorbital model incorporating full dynamical electronic correlations.
• Included the effects of Hubbard U and Hund's coupling.
• Analyzed superconductivity driven by a generic bosonic mechanism.

Main Results:

• Superconductivity persists more robustly in a Hund's metal than in an ordinary correlated metal with similar correlation levels.
• The characteristic redistribution of spectral weight in Hund's metals enhances orbital-selective superconducting gaps.
• Results are consistent with experimental findings in iron-based superconductors.

Conclusions:

• Hund's coupling plays a vital role in stabilizing superconductivity in multiorbital systems.
• The Hund's metal phase offers a promising avenue for achieving higher-temperature superconductivity.
• The study provides a theoretical framework explaining experimental observations in iron-based superconductors.