Effect of holephonon interaction on d_x~2- _y~2-wave superconducting phase in 2D t-J model with phonon mediated interaction

摘要

Ground-state properties of the 2D t-J model with phonon mediated interaction are examined by an exact diagonalization method, following the idea that a local lattice distortion occurs in association with hole upon doping. Effect of this phonon mediated interaction on d-wave pairing over the pure t-J model has been shown. Results show an influence of phonon mediated interaction on d-wave pairing state. Formation of a less mobile quasi-particle made of holepolaron accompanied by a hole at nearest-neighbor site, eventually supports d-wave pairing. It is also shown that increase in coupling strength forms inter-site holebipolaron which gradually decrease d-wave pairing strength. Results show that role of phonons in the mechanism of high temperature superconductivity is very much relevant.