2008/03/31 by Q. Han, Qiang Han, Y. Chen +1 · 10 citations
Materials Science · Mathematics · Physics and Astronomy · #Condensed matter physics #Doping #Electron #Electronic band structure #Hamiltonian (control theory) #Hubbard model #Iron-based superconductors research #Mathematics #Pairing #Phase (matter) #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Rare-earth and actinide compounds #Superconductivity #cond-mat.supr-con #t-J model
paper · pdf · doi:10.1209/0295-5075/82/37007
published as A slightly modified version published online 23 April 2008 in EPL, 82 (2008) 37007 · 6 pages, 4 figures, refs. added, typos corrected
arxiv created 2008/04/12 · openalex publication_date 2008/04/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Based on experimental data on the newly synthesized iron-based superconductors and the relevant band structure calculations, we propose a minimal two-band BCS-type Hamiltonian with the interband Hubbard interaction included. We illustrate that this two-band model is able to capture the essential features of unconventional superconductivity and spin-density-wave (SDW) ordering in this family of materials. It is found that bound electron-hole pairs can be condensed to reveal the SDW ordering for zero and very small doping, while the superconducting ordering emerges at small finite doping, whose pairing symmetry is qualitatively analyzed to be of nodal d -wave. The derived analytical formulas not only give out a nearly symmetric phase diagram for electron and hole doping, but also are likely able to account for existing main experimental results. Moreover, we also derive two important relations for a general two-band model and elaborate how to apply them to determine the band width ratio and the effective interband coupling strength from experimental data.