Spin dynamics in D-wave superconductors.

Abstract

The dynamic spin-correlation function in the superconducting states (i.e., D wave and S wave) in the vicinity of the commensurate point Q=(\ensuremath{\pi},\ensuremath{\pi}) 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\ensuremath{\ge}${\mathit{T}}_{\mathit{c}}$ 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.