Antiferromagnetic order in multi-band Hubbard models for iron-pnictides

Abstract

We investigate multi-band Hubbard models for the three iron 3$d$-$t_{2g}$ bands and the two iron 3$d$-$e_g$ bands in $\mathrm{LaOFeAs}$ by means of the Gutzwiller variational theory. Our analysis of the paramagnetic ground state shows that neither Hartree--Fock mean-field theories nor effective spin models describe these systems adequately. In contrast to Hartree--Fock-type approaches, the Gutzwiller theory predicts that antiferromagnetic order requires substantial values of the local Hund's-rule exchange interaction. For the three-band model, the antiferromagnetic moment fits experimental data for a broad range of interaction parameters. However, for the more appropriate five-band model, the iron $e_g$ electrons polarize the $t_{2g}$ electrons and they substantially contribute to the ordered moment.

4 pages, 4 figures

References in corpus (5)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• The challenge of unravelling magnetic properties in LaFeAsO
• Itinerant Nature of Magnetism in Iron Pnictides: A first principles study
• Phase transitions and iron-ordered moment form factor in LaFeAsO

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• Quantum-embedding description of the Anderson lattice model with the ghost Gutzwiller Approximation
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• Fingerprints of spin-orbital polarons and of their disorder in the photoemission spectra of doped Mott insulators with orbital degeneracy
• Gutzwiller variational wave function for multi-orbital Hubbard models in finite dimensions
• The time-dependent Gutzwiller theory for multi-band Hubbard models
• Quasi-particle bands and structural phase transition of iron from Gutzwiller Density-Functional Theory
• Influence of electronic correlations on orbital polarizations in the parent and doped iron pnictides
• Approximation schemes for the study of multi-band Gutzwiller wave functions
• Two-orbital quantum spin model of magnetism in the iron pnictides
• Band antiferromagnetism in a two-band model for iron pnictides