Interplay between strong correlations and electron‐phonon coupling in cuprates: Comparison between different models

摘要

We investigate influence of electron‐phonon coupling on physics of lightly doped cuprates. Using an exact‐diagonalization technique defined over a limited functional space we compare properties of two doped holes propagating in an antiferromagnetic (AFM) background, coupled to quantum phonons in two alternative ways. In the first model phonons interact with hole density via Holstein coupling leading to the t‐J Holstein model, and in the second model lattice vibrations modify the hole hopping in the effective t‐J model. We show that the former lead to stabilization of d‐wave pairing, while in the latter case a state with p‐wave symmetry is favored. The results emphasize a subtle interplay between electronic correlations and lattice vibrations in cuprates as well as the importance of different modeling of e‐ph interaction.