We show that in quasi-two-dimensional d-wave superconductors van Hove singularities close to the Fermi surface lead to magnetic quasiparticle excitations. We calculate the temperature and doping dependence of dynamical magnetic susceptibility for YBa2Cu3O6+x and show that the proposed excitations are in agreement with inelastic-neutron-scattering experiments. In addition, the values of the gap parameter and in-plane antiferromagnetic coupling are much smaller than usually believed.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics