Spin fluctuations ofd-wave superconductors

The dynamic spin correlation function near the commensurate point Q=({π},{π}) in the superconducting state is calculated within mean field theory. We take the generalized t-J model as used by Tanamoto et al. For d-wave superconductor at T=0 K, we find that there will be no energy gap at incommensurate point, while the energy gap Eg=2{μ} develops at commensurate point in the particle-hole channel. On the other hand for s-wave superconductor a large energy gap develops irrespective of the nature of antiferromagnetic fluctuations. Therefore the d-wave model describes the neutron scattering data from both La1.86{Sr}0.14CuO₄ by Mason et al. and YBa₂{Cu}₃O₆₊ₓ by Rossat-Mignod et al. quite well, while the s-wave model is incompatible with these experimental results.