title: Quasiparticle self-consistent GW study of cuprates: electronic structure, model parameters, and the two-band theory for Tc.
abstract: Despite decades of progress, an understanding of unconventional superconductivity still remains elusive. An important open question is about the material dependence of the superconducting properties. Using the quasiparticle self-consistent GW method, we re-examine the electronic structure of copper oxide high-Tc materials. We show that QSGW captures several important features, distinctive from the conventional LDA results. The energy level splitting between d(x(2)-y(2)) and d(3z(2)-r(2)) is significantly enlarged and the van Hove singularity point is lowered. The calculated results compare better than LDA with recent experimental results from resonant inelastic xray scattering and angle resolved photoemission experiments. This agreement with the experiments supports the previously suggested two-band theory for the material dependence of the superconducting transition temperature, Tc.
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Jang
authors.affiliation: Department of Applied Mathematics and Physics, Tottori University, Tottori 680-8552, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Kotani
authors.affiliation: National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Hiori
authors.initials: H
authors.lastname: Kino
authors.affiliation: Department of Physics, Osaka University, Machikaneyama-Cho, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kuroki
authors.affiliation: 1] Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea [2] KAIST Institute for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
authors.forename: Myung Joon
authors.initials: MJ
authors.lastname: Han