Bipolaron in the t-J model coupled to longitudinal and transverse quantum lattice vibrations

TL;DR

This study investigates how different quantum lattice vibrations influence the symmetry and properties of bipolarons in the t-J model, revealing polarization-dependent symmetry stabilization and mass anisotropy.

Contribution

It demonstrates the role of transverse and longitudinal phonon couplings in determining bipolaron symmetry and effective mass within the t-J model using exact diagonalization.

Findings

Quadratic coupling to transverse vibrations stabilizes d-wave symmetry.

Magnetic background is crucial for d-wave bipolaron formation.

Increasing linear coupling to longitudinal vibrations shifts symmetry to p-wave.

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. Quadratic electron phonon coupling to transverse polarization stabilizes 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.