MRSej, Vol. 6, No.1, pp.21-32, 2004

 

POLARON EFFECTS IN EXTENDED HUBBARD MODEL

 

I. Eremin1, M.V. Eremin2

1 Institut für Theoretische Physik, Freie Universität, Berlin, Germany

2 Physics Department, Kazan State University, 420008 Kazan, Russia

 

Starting from the three-band p-d Hubbard Hamiltonian we derive the effective t-J model Hamiltonian including electron-phonon interaction of quasiparticles with optical phonons and strong electron correlations. We consider two possible cases when the carriers move over the oxygen sites and also if the they move over the copper sublattice. Most importantly, we find that the phonon renormalization of t is quite different in both cases. Within an effective Hamiltonian we analyze the influence of phonons on the dynamical spin susceptibility in layered cuprates. For example, we find an isotope effect on resonance peak in the magnetic spin susceptibility, Im\chi(q,\omega), seen by inelastic neutron scattering. It experimental observation would be a strong argument in favor of polaronic character of the carrier motion in layered cuprates.

 

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