SPECTRAL PROPERTIES OF THE T-J MODEL IN THE PRESENCE OF HOLE-PHONON INTERACTION

We examine the effects of electron-phonon interaction on the dynamics of the charge carriers doped in two-dimensional (2D) Heisenberg antife rromagnet. The t-J model Hamiltonian with a Frohlich term which couple s the holes to a dispersionless (optical) phonon mode is considered fo r low doping concentration. The evolution of the spectral density func tion, the density of states, and the momentum distribution function of the holes with an increase of the hole-phonon coupling constant g is studied numerically. As the coupling to a phonon mode increases the qu asiparticle spectral weight decreases and a ''phonon satellite'' featu re close to the quasiparticle peak becomes more pronounced. Furthermor e, strong electron-phonon coupling smears the multimagnon resonances ( ''string states'') in the incoherent part of the spectral function. Th e jump in the momentum distribution function at the Fermi surface is r educed without changing the hole pocket volume, thereby providing a nu merical verification of Luttinger theorem for this strongly interactin g system. The vertex corrections due to electron-phonon interaction ar e negligible in spite of the fact that the ratio of the phonon frequen cy to the effective bandwidth is not small.