arXiv:cond-mat/0411151 · Physical Review B
Phase diagram of the t−U−V1−V2 model at quarter filling
Satoshi Ejima, Florian Gebhard, Satoshi Nishimoto, Y. Ohta
Abstract
We examine the ground-state properties of the one-dimensional Hubbard model at quarter filling with Coulomb interactions between nearest-neighbors ${V}_{1}$ and next-nearest neighbors ${V}_{2}$. Using the density-matrix renormalization group and exact diagonalization methods, we obtain for $U=10t$ three different phases in the ${V}_{1}\text{\ensuremath{-}}{V}_{2}$ plane: $2{k}_{\mathrm{F}}$- and $4{k}_{\mathrm{F}}$-charge-density-wave (CDW) and a broad metallic phase in between. Assuming that the metal is a Tomonaga-Luttinger liquid (TLL), we calculate the TLL parameter ${K}_{\ensuremath{\rho}}$. It is largest when ${V}_{1}$ and ${V}_{2}$ are frustrated, and ${K}_{\ensuremath{\rho}}=0.25$ at the boundaries between the metallic phase and each of the two CDW phases.