The resonance peak in cuprate superconductors

We pursue the consequences of a theory in which the resonance peak observed in inelastic neutron scattering experiments on underdoped and optimally doped YBa2Cu3O6+x compounds arises from a spin-wave excitation. We find that it is heavily damped in the normal state and only becomes visible in the superconducting state due to the drastic decrease in spin damping. We show that a spin-fermion model correctly describes the doping dependence of the peak position and of the integrated intensity. Finally, we make several predictions concerning resonance peaks in other cuprate superconductors.