K. Yonemitsu et M. Imada, ELECTRON-PHONON INTERACTION AND SPIN GAP IN NEARLY-HALF-FILLED CORRELATED ELECTRON-SYSTEMS, Physica. C, Superconductivity, 263(1-4), 1996, pp. 82-85
Renormalization-group equations are solved to study phase diagrams of
nearly-half-filled one-dimensional conductors interacting with phonons
. A spin-gap charge density wave phase exists between a gapless densit
y wave phase and a spin-gap superconductor phase. On-site and intersit
e electron-phonon couplings show large differences near half-filling i
n the presence of on-site electron repulsion.