Unified Picture for Magnetic Correlations in Iron-Based Superconductors

TL;DR

This paper presents a unified model explaining the diverse magnetic correlations in iron-based superconductors by balancing itinerant electron behavior and localized spins, emphasizing Hund's rule coupling's role.

Contribution

It introduces a comprehensive model that unifies magnetic behaviors in iron-based superconductors, highlighting the competition between superexchange and double-exchange mechanisms.

Findings

Hund's rule coupling is crucial for strong correlations.

Magnetism in iron-based superconductors resembles manganites more than cuprates.

The model explains the incoherent normal-state electron transport.

Abstract

The varying metallic antiferromagnetic correlations observed in iron-based superconductors are unified in a model consisting of both itinerant electrons and localized spins. The decisive factor is found to be the sensitive competition between the superexchange antiferromagnetism and the orbital-degenerate double-exchange ferromagnetism. Our results reveal the crucial role of Hund's rule coupling for the strongly correlated nature of the system and suggest that the iron-based superconductors are closer kin to manganites than cuprates in terms of their diverse magnetism and incoherent normal-state electron transport. This unified picture would be instrumental for exploring other exotic properties and the mechanism of superconductivity in this new class of superconductors.