Possible isotope effect on the resonance peak formation in high-T_c cuprates
Abstract
Starting from the three-band p-d Hubbard Hamiltonian we derive an effective t-J model including electron-phonon interaction of quasiparticles with optical phonons. Within the effective Hamiltonian we analyze the influence of electronic correlations and electron-phonon interaction on the dynamical spin susceptibility in layered cuprates. We find a huge isotope effect on the resonance peak in the magnetic spin susceptibility, {Im}\chi({\bf q},\omega), seen by inelastic neutron scattering. It results from both the electron-phonon coupling and the electronic correlation effects taken into account beyond random phase approximation(RPA) scheme. We find at optimal doping the isotope coeffiecient \alpha_{res} \approx 0.35 which can be further tested experimentally.