Three-body scattering theory for strongly correlated electron system

1.We have calculated the spectra of single-particle excitations on the realistic tight-binding models for LaCuO I D24文件D2 and Sr I D22文件D2 CuO文件D22文件D2Cl文件D22文件D2，which are prototypical antiferromagnetic insulators and the parent compounds of high-Tc superconductors.To deal with strong correlation effects，we have calculated the self-energy for the single-particle Green‘s function by using the the local three-body scattering approximation，which considers multiple scatterings between three particles excited on the Hartree-Fock(HF)ground state。The present method improved greatly the HF results，leading to good agreement with the photoemission experiments.2。We have developed a three-body scattering theory to apply to the saturated ferromagnetic state in the two-dimensional Hubbard model。Solving directly the Faddeev@equation，we have improved previous variational results.3。We have proposed an approximate version of the three-body scattering theory as an extension of local approximat…More ion；the three-body problem is solved by limiting the number of three-body states。Applying this simple extension to the antiferromagnetic state at half-filling in the two-dimensional Hubbard model，we have demonstrated that it gives a reasonable spectral function for the single-particle Green‘s function in compararison with the results of the exact diagonalization for finite clusters and the quantum Monte Carlo method.4。We have calculated the resonant X-ray scattering intensity for LaMnO I D23 ii D2 using the band calculation based on the local density approximation。We have shown that the Jahn-Teller distortion gives rise to large AXS intensities by modifying the 4p states of Mn through the oxygen potential on the neighboring sites.We have also studied the pre-K-edge structure，and have found a two-peak structure with the intensity~1/100times as small as that of the main peak.This originates from the 4p states of Mn mixing to the 3d states of neighboring Mn sites，and a reflection of the orbital order.Less：Less

1. We have calculated the spectra of single-particle excitations on the realistic tight-binding models for LaCuOィイD24ィエD2 and SrィイD22ィエD2CuOィイD22ィエD2ClィイD22ィエD2, which are prototypical antiferromagnetic insulators and the parent compounds of high-Tc superconductors. To deal with strong correlation effects, we have calculated the self-energy for the single-particle Green's function by using the the local three-body scattering approximation, which considers multiple scatterings between three particles excited on the Hartree-Fock (HF) ground state. The present method improved greatly the HF results, leading to good agreement with the photoemission experiments.2. We have developed a three-body scattering theory to apply to the saturated ferromagnetic state in the two-dimensional Hubbard model. Solving directly the Faddeev equation, we have improved previous variational results.3. We have proposed an approximate version of the three-body scattering theory as an extension of local approximat … More ion ; the three-body problem is solved by limiting the number of three-body states. Applying this simple extension to the antiferromagnetic state at half-filling in the two-dimensional Hubbard model, we have demonstrated that it gives a reasonable spectral function for the single-particle Green's function in compararison with the results of the exact diagonalization for finite clusters and the quantum Monte Carlo method.4. We have calculated the resonant X-ray scattering intensity for LaMnOィイD23ィエD2 using the band calculation based on the local density approximation. We have shown that the Jahn-Teller distortion gives rise to large AXS intensities by modifying the 4p states of Mn through the oxygen potential on the neighboring sites. We have also studied the pre-K-edge structure, and have found a two-peak structure with the intensity 〜 1/100 times as small as that of the main peak. This originates from the 4p states of Mn mixing to the 3d states of neighboring Mn sites, and a reflection of the orbital order. Less