Novel Density-Wave States of Two-Band Peierls-Hubbard Chains
Based on a symmetry argument we systematically reveal Hartree-Fock broken-symmetry solutions of the one-dimensional two-band extended Peierls-Hubbard model, which covers various materials of interest such as halogen-bridged metal complexes and mixed-stack charge-transfer salts. We find out all the regular-density-wave solutions with an ordering vector $q=0$ or $q=\pi$. Changing band filling as well as electron-electron and electron-phonon interactions, we numerically inquire further into the ground-state phase diagram and the physical property of each state. The possibility of novel density-wave states appearing is argued.