Spin dynamics inD-wave superconductors

The dynamic spin-correlation function in the superconducting states (i.e., D wave and S wave) in the vicinity of the commensurate point Q=(π,π) is obtained within mean-field theory. As a model we take the generalized t-J model as analyzed by Tanamoto, Kohno, and Fukuyama though we interpret the fermion loop as associated with a renormalized hole. For T≥${\mathit{T}}_{\mathit{c}}$ where ${\mathit{T}}_{\mathit{c}}$ is the superconducting transition temperature our result is essentially the same as Tanamoto, Kohno, and Fukuyama, but the superconducting correlation is easily incorporated within the present scheme. We find recent neutron-scattering data from both ${\mathrm{La}}_{1.86}$ ${\mathrm{Sr}}_{0.14}$ ${\mathrm{CuO}}_4$ by Mason et al. and ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{6+\mathit{x}}$ by Rossat-Mignod et al. are consistent with the D-wave model but incompatible with the S-wave model.