Spin dynamics in HTSC cuprates: The singlet--correlated band (or t-J-V) model and its applications

摘要

So far calculations of the spin susceptibility in the superconducting stateof cuprates have been performed in the framework of weak-couplingapproximations. However, it is known that cuprates belong to Mott-Hubbard dopedmaterials where electron correlations are important. In this paper ananalytical expression for the spin susceptibility in the superconducting stateof cuprates is derived within the singlet-correlated band model, which takesinto account strong correlations. The expression of the spin susceptibility isevaluated using values for the hopping parameters adapted to measurements ofthe Fermi surface of the materials YBa2Cu3O7 and Bi2Sr2CaCu2O8. We show thatthe available experimental data which are directly related to the spinsusceptibility can be explained consistently within one set of model parametersfor each material. These experiments include the magnetic resonance peakobserved by inelastic neutron scattering and the temperature dependence of theNMR spin shift, spin-spin and spin-lattice relaxation rates in thesuperconducting state.