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@ARTICLE{Liebsch:2327,
      author       = {Liebsch, A. and Ishida, H. and Merino, J.},
      title        = {{M}ultisite versus multiorbital {C}oulomb correlations
                      studied within finite-temperature exact diagonalization
                      dynamical mean-field theory},
      journal      = {Physical review / B},
      volume       = {78},
      number       = {16},
      issn         = {1098-0121},
      address      = {College Park, Md.},
      publisher    = {APS},
      reportid     = {PreJuSER-2327},
      pages        = {165123},
      year         = {2008},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {The influence of short-range Coulomb correlations on the
                      Mott transition in the single-band Hubbard model at half
                      filling is studied within cellular dynamical mean-field
                      theory for square and triangular lattices.
                      Finite-temperature exact diagonalization is used to
                      investigate correlations within two-, three-, and four-site
                      clusters. Transforming the nonlocal self-energy from a site
                      basis to a molecular-orbital basis, we focus on the
                      interorbital charge transfer between these cluster molecular
                      orbitals in the vicinity of the Mott transition. In all
                      cases studied, the charge transfer is found to be small,
                      indicating weak Coulomb-induced orbital polarization despite
                      sizable level splitting between orbitals. These results
                      demonstrate that all cluster molecular orbitals take part in
                      the Mott transition and that the insulating gap opens
                      simultaneously across the entire Fermi surface. Thus, at
                      half filling we do not find orbital-selective Mott
                      transitions or a combination of band filling and Mott
                      transition in different orbitals. Nevertheless, the approach
                      toward the transition differs greatly between cluster
                      orbitals, giving rise to a pronounced momentum variation
                      along the Fermi surface, in agreement with previous works.
                      The near absence of Coulomb-induced orbital polarization in
                      these clusters differs qualitatively from single-site
                      multiorbital studies of several transition-metal oxides,
                      where the Mott phase exhibits nearly complete orbital
                      polarization as a result of a correlation driven enhancement
                      of the crystal-field splitting. The strong single-particle
                      coupling among cluster orbitals in the single-band case is
                      identified as the source of this difference.},
      keywords     = {J (WoSType)},
      cin          = {IFF-1},
      ddc          = {530},
      cid          = {I:(DE-Juel1)VDB781},
      pnm          = {Kondensierte Materie},
      pid          = {G:(DE-Juel1)FUEK414},
      shelfmark    = {Physics, Condensed Matter},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000260574500044},
      doi          = {10.1103/PhysRevB.78.165123},
      url          = {https://juser.fz-juelich.de/record/2327},
}