title: Bipolaron in the t-J model coupled to longitudinal and transverse quantum lattice vibrations.
abstract: We explore the influence of two different polarizations of quantum oxygen vibrations on the spacial symmetry of the bound magnetic bipolaron in the context of the t-J model by using exact diagonalization within a limited functional space. Linear as well as quadratic electron-phonon coupling to transverse polarization stabilize d-wave symmetry. The existence of a magnetic background is essential for the formation of a d-wave bipolaron state. With increasing linear electron-phonon coupling to longitudinal polarization the symmetry of a d-wave bipolaron state changes to a p wave. Bipolaron develops a large anisotropic effective mass.
authors.affiliation: J. Stefan Institute, 1000 Ljubljana, Slovenia.
authors.forename: L
authors.initials: L
authors.lastname: Vidmar
authors.forename: J
authors.initials: J
authors.lastname: Bonca
authors.forename: S
authors.initials: S
authors.lastname: Maekawa
authors.forename: T
authors.initials: T
authors.lastname: Tohyama