2004/09/18 by K. Ishii, Kenji Ishii, K. Tsutsui +17 · 6 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.94.187002
published as Phys. Rev. Lett. 94, 187002 (2005)
arxiv created 2004/09/18 · openalex publication_date 2005/05/12 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Mott gap excitations in the optimally doped high-Tc superconductor YBa2Cu3O_7\ensuremath-\ensuremathδ (Tc=93 K) have been studied by the resonant inelastic x-ray scattering method. Anisotropic spectra in the ab plane are observed in a twin-free crystal. The excitation from the one-dimensional CuO chain is enhanced at 2 eV near the zone boundary of the \mathbitb* direction, while the excitation from the CuO2 plane is broad at 1.5--4 eV and almost independent of the momentum transfer. Theoretical calculations based on the one-dimensional and two-dimensional Hubbard model reproduces the observed spectra when different values of the on-site Coulomb energy are assumed. The Mott gap of the CuO chain site is found to be much smaller than that of the CuO2 plane site.