Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.343, 539-544, 2000
Collective excitations around charge ordered states and coexistent states with different orders
We study qualitative differences of excited states between a charge ordered state and a charge uniform state. The excited states are calculated in the random phase approximation for the one-dimensional extended Hubbard model at quarter Filling. In the charge ordered state, a dominant excitation in the current-current correlation function has no charge density modulation. A dominant excitation in the charge uniform state originates from crossing the dimerization gap and modulates the charge density.
Keywords:charge ordering;linear excitation;intersite Coulomb repulsion;Hartree-Fock approximation;random phase approximation