2008/12/15 by Rong Yu, Kien Trinh, Kien T. Trinh +6 · 67 citations
Materials Science · Physics and Astronomy · #Antiferromagnetism #Condensed matter physics #Coupling (piping) #Hubbard model #Iron-based superconductors research #Materials science #Mean field theory #Physics #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Superconductivity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.79.104510
published in Physical Review B 79(10) (American Physical Society) · 18 pages, 23 figures
arxiv created 2008/12/15 · openalex publication_date 2009/03/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Multiorbital Hubbard model Hamiltonians for the undoped parent compounds of the Fe-pnictide superconductors are investigated here using mean-field techniques. For a realistic four-orbital model, our results show the existence of an intermediate Hubbard U coupling regime where the mean-field ground state has a (\ensuremathπ,0) antiferromagnetic order, as in neutron-scattering experiments, while remaining metallic due to the phenomenon of band overlaps. The angle-resolved photoemission intensity and Fermi surface of this magnetic and metallic state are discussed. Other models are also investigated, including a two-orbital model where not only the mean-field technique can be used but also the exact diagonalization in small clusters and the variational cluster approximation in the bulk. The combined results of the three techniques point toward the existence of an intermediate-coupling magnetic and metallic state in the two-orbital model, similar to the intermediate-coupling mean-field state of the four-orbital model. We conclude that the state discussed here is compatible with the experimentally known properties of the undoped Fe pnictides.