https://doi.org/10.1140/epjb/e2005-00098-2
Charge gaps and quasiparticle bands of the ionic Hubbard model
1
Institut für Festkörperphysik,
Technische Universität Darmstadt, 64289 Darmstadt, Germany
2
Fachbereich 1, Universität Bremen, 28334 Bremen, Germany
Corresponding author: a torben@fkp.tu-darmstadt.de
Received:
15
November
2004
Revised:
14
January
2005
Published online:
16
April
2005
The ionic Hubbard model on a cubic lattice is investigated using analytical approximations, the DMFT and Wilson's renormalization group for the charge excitation spectrum. Near the Mott insulating regime, where the Hubbard repulsion starts to dominate all energies, the formation of correlated bands is described. The corresponding partial spectral weights and local densities of states show the characteristic features, of a hybridized-band structure as appropriate for the regime at small U, which at half-filling is known as a band insulator. In particular, a narrow charge gap is obtained at half-filling, and the distribution of spectral quasi-particle weight reflects the fundamental hybridization mechanism of the model.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 71.10.Fd – Lattice fermion models (Hubbard model, etc.) / 71.10.+h – Metal-insulator transitions and other electronic transitions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005
