2007/02/28 by Katsunori Kubo · 5 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Antisymmetric relation #Atomic orbital #Condensed matter physics #Electron #Hubbard model #Magnetic and transport properties of perovskites and related materials #Mathematical physics #Non-bonding orbital #Pairing #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Square lattice #Superconductivity #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.75.224509
published as Phys. Rev. B 75, 224509 (2007) · 9 pages, 6 figures
openalex publication_date 2007/06/14 · arxiv created 2007/06/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate superconductivity in a two-orbital Hubbard model on a square lattice by applying fluctuation exchange approximation. In the present model, the symmetry of the two orbitals are assumed to be that of an s orbital. Then, we find that an s-wave spin-triplet orbital-antisymmetric state and a p-wave spin-singlet orbital-antisymmetric state appear when Hund's rule coupling is large. These states are prohibited in a single-orbital model within states with even frequency dependence, but allowed for multiorbital systems. We also discuss pairing symmetry in other models which are equivalent to the two-orbital Hubbard model except for symmetry of orbitals. Finally, we show that pairing states with a finite total momentum, even without a magnetic field, are possible in a system with two Fermi surfaces.