Selective Mott physics as a key to iron superconductors.
We show that electron- and hole-doped BaFe(2)As(2) are strongly influenced by a Mott insulator that would be realized for half-filled conduction bands. Experiments show that weakly and strongly correlated conduction electrons coexist in much of the phase diagram, a differentiation which increases with hole doping. This selective Mottness is caused by the Hund's coupling effect of decoupling the charge excitations in different orbitals. Each orbital then behaves as a single-band doped Mott insulator, where the correlation degree mainly depends on how doped is each orbital from half filling. Our scenario reconciles contrasting evidences on the electronic correlation strength, implies a strong asymmetry between hole and electron doping, and establishes a deep connection with the cuprates.
Laboratoire de Physique et Etude des Matériaux, UMR8213 CNRS/ESPCI/UPMC, Paris, France and Laboratoire de Physique des Solides, UMR8502 CNRS-Université Paris-Sud, Orsay, France and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex 9, France.
Luca
L
de' Medici
CNR-IOM-Democritos National Simulation Centre and International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136, Trieste, Italy.
Gianluca
G
Giovannetti
CNR-IOM-Democritos National Simulation Centre and International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136, Trieste, Italy.
Massimo
M
Capone