The single-polaron band structure of the Holstein model in one and two dimensions is studied using resummed strong-coupling perturbation theory. Well-converged results are obtained for phonon frequencies of the order of the hopping integral and strong-to-intermediate electron-phonon coupling. The polaron band structure at intermediate coupling is shown to deviate markedly from that of a nearest-neighbor tight-binding model and is in fact similar in shape to the prediction of weak-coupling self-consistent perturbation theory. © 1996 The American Physical Society.

• Received 10 June 1996

DOI:https://doi.org/10.1103/PhysRevB.54.8981