Metal-insulator transition and charge ordering in the extended Hubbard model at one-quarter filling
arXiv:cond-mat/0202219 · doi:10.1103/PhysRevB.66.195102
Abstract
We study with exact diagonalization the zero temperature properties of the quarter-filled extended Hubbard model on a square lattice. We find that increasing the ratio of the intersite Coulomb repulsion, $V$, to the band width drives the system from a metal to a charge ordered insulator. The evolution of the optical conductivity spectrum with increasing $V$ is compared to the observed optical conductivity of several layered molecular crystals with the theta and beta'' crystal structures.
5 pages, 3 figures