Phase diagram of the extended hubbard model with pair hopping interaction

  • G.I. Japaridze
  • S. Sarkar


A one-dimensional model of interacting electrons with on-site U, nearest-neighbor V, and pair-hopping interaction W is studied at half-filling using the continuum limit field theory approach. The ground state phase diagram is obtained for a wide range of coupling constants. In addition to the insulating spin-density wave (SDW) and charge-density wave (CDW) phases for large U and V, respectively, we identify a bond-charge-density-wave (BCDW) phase W < 0, | U - 2V| < | 2W| and a bond-spin-density-wave (BSDW) for W > 0, | U - 2V| < W. The possibility of bond-located ordering results from the site-off-diagonal nature of the pair-hopping term and is a special feature of the half-filled band case. The BCDW phase corresponding to an enhanced Peierls instability in the system. The BdSDW is an unconventional insulating magnetic phase, characterized by a gapless spin excitation spectrum and a staggered magnetization located on bonds between sites. The general ground state phase diagram including insulating, metallic, and superconducting phases is discussed. A transition to the η-superconducting phase at | U - 2V| ≪ 2t?W is briefly discussed.

PACS. 71.27.+a Strongly correlated electron systems; heavy fermions – 71.10.Hf Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems – 71.10.Fd Lattice fermion models (Hubbard model, etc.) 


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Copyright information

© EDP Sciences, Springer-Verlag 2002

Authors and Affiliations

  • G.I. Japaridze
    • 1
  • S. Sarkar
    • 2
  1. 1.Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187, Dresden, GermanyDE
  2. 2.Institute of Physics, Georgian Academy of Sciences, Tamarashvili Str. 6, 380077, Tbilisi, GeorgiaGE

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