Polaron and bipolaron formation in the Hubbard-Holstein model: Role of next-nearest-neighbor electron hopping
G. De Filippis, V. Cataudella, Giuseppe Iadonisi +3 more
The influence of next-nearest-neighbor electron hopping ${t}^{\ensuremath{'}}$ on the polaron and bipolaron formation in a square Hubbard-Holstein model is investigated within a variational approach. The results for electron-phonon and electron-electron correlation functions show that a negative value of ${t}^{\ensuremath{'}}$ induces a strong anisotropy in the lattice distortions favoring the formation of nearest-neighbor intersite bipolaron. The role of ${t}^{\ensuremath{'}},$ electron-phonon and electron-electron interactions is briefly discussed in view of the formation of charged striped domains.
arXiv:cond-mat/0106586•Physical review. B, Condensed matter•Sep 19, 2001•12 citations