POLARONIC EFFECTS IN STRONGLY COUPLED ELECTRON-PHONON SYSTEMS - EXACTDIAGONALIZATION RESULTS FOR THE 2D HOLSTEIN T-J MODEL

Ground-state and dynamical properties of the 2D Holstein t-J model are examined by means of direct Lanczos diagonalization, using a truncati on method of the phononic Hilbert space. The single-hole spectral func tion shows the formation of a narrow hole-polaron band as the electron -phonon coupling increases, where the polaronic band collapse is favou red by strong Coulomb correlations. In the two-hole sector, the hole-h ole correlations unambiguously indicate the existence of inter-site bi polaronic states. At quarter-filling, a polaronic superlattice is form ed in the adiabatic strong-coupling regime.