HOLE PAIRING AND PHONON DYNAMICS IN GENERALIZED TWO-DIMENSIONAL T-J HOLSTEIN MODELS

The formation of hole pairs in the planar t-J model is studied in the presence of independent dynamic vibrations of the in-plane oxygen atoms. In-plane (breathing modes) and out-of-plane (buckling modes) displacements are considered. We find strong evidence in favor of a stabilization of the two-hole bound pair by out-of-plane vibrations of the in-plane oxygens. On the contrary, the breathing modes weaken the binding energy of the hole pair. When properly dressed by oxygen buckling fluctuations, the hole-pair propagator exhibits a large quasiparticlelike peak. These results are discussed in the context of superconducting cuprates.