title: Unified picture for magnetic correlations in iron-based superconductors.
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.
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA. wyin@bnl.gov
authors.forename: Wei-Guo
authors.initials: WG
authors.lastname: Yin
authors.forename: Chi-Cheng
authors.initials: CC
authors.lastname: Lee
authors.forename: Wei
authors.initials: W
authors.lastname: Ku