https://doi.org/10.1140/epjb/e2002-00212-0
Phase diagram of the extended hubbard model with pair hopping interaction
1
Max-Planck-Institut für Physik komplexer Systeme,
Nöthnitzer Str. 38, 01187, Dresden, Germany
2
Institute of Physics, Georgian Academy of Sciences,
Tamarashvili Str. 6, 380077, Tbilisi, Georgia
Corresponding author: a giajaparidze@gol.ge
Received:
20
February
2002
Revised:
11
April
2002
Published online:
19
July
2002
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, 
and a
bond-spin-density-wave (BSDW) for W>0, 
. 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 
-superconducting
phase at 
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.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002
