Effects of Next-Nearest-Neighbor Repulsion on One-Dimensional   Quarter-Filled Electron Systems
  We examine effects of the next-nearest-neighbor repulsion on electronic states of a one-dimensional interacting electron system which consists of quarter-filled band and interactions of on-site and nearest-neighbor repulsion. We derive the effective Hamiltonian for the electrons around wave number $\pm \kf$ ($\kf$: Fermi wave number) and apply the renormalization group method to the bosonized Hamiltonian. It is shown that the next-nearest-neighbor repulsion makes $4\kf$-charge ordering unstable and suppresses the spin fluctuation. Further the excitation gaps and spin susceptibility are also evaluated. 
H. Yoshioka (Nara Women's Univ.), M. Tsuchiizu (Nagoya Univ.), Y.   Suzumura (Nagoya Univ.)