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Neutron and ARPES constraints on the couplings of the multiorbital Hubbard model for the iron pnictides

Journal Article · · Physical Review B
The results of neutron-scattering and angle-resolved photoemission experiments for the Fe-pnictide parent compounds, and their metallic nature, are shown to impose severe constraints on the range of values that can be considered realistic for the intraorbital Hubbard repulsion U and Hund coupling J in multiorbital Hubbard models treated in the mean-field approximation. Phase diagrams for three- and five-orbital models are here provided, and the physically realistic regime of couplings is highlighted, to guide future theoretical work into the proper region of parameters of Hubbard models. In addition, using the random phase approximation, the pairing tendencies in these realistic coupling regions are investigated. It is shown that the dominant spin-singlet pairing channels in these coupling regimes correspond to nodal superconductivity, with strong competition between several states that belong to different irreducible representations. This is compatible with experimental bulk measurements that have reported the existence of nodes in several Fe-pnictide compounds.
Research Organization:
Oak Ridge National Laboratory (ORNL)
Sponsoring Organization:
SC USDOE - Office of Science (SC)
DOE Contract Number:
AC05-00OR22725
OSTI ID:
1009944
Journal Information:
Physical Review B, Journal Name: Physical Review B Journal Issue: 10 Vol. 82; ISSN 1098-0121
Country of Publication:
United States
Language:
English