Spin-Peierls ground states and frustration in a multiband Peierls-Hubbard model

Abstract
We discuss the consequences of including both electron-phonon and electron-electron couplings in multiband models, focusing on numerical studies of a one-dimensional two-band model in the intermediate regime for both coupling strengths. Spin-Peierls as well as long-period, frustrated ground states are identified, reminiscent of those found in axial next-nearest-neighbor Ising models. We speculate on experimentally observable signatures of this rich phase diagram.