The resonance peak in the high-T-c cuprates

I present a theory in which the resonance peak observed in inelastic neutro n scattering experiments on YBa2Cu3O6+x and Bi2Sr2CaCu2O8+x. arises from a dispersing spin mode. I argue that it is heavily damped in the normal state and becomes visible in the superconducting state due to a drastic decrease in the spin damping. I show thar a spin-fermion model correctly describes the doping dependence of the peak position and of its integrated intensity. Finally, I derive a criterion for the existence of the resonance peak in o ther cuprate superconductors. (C) 2000 Published by Elsevier Science B.V. A ll rights reserved.