Mean-field study of the interplay between antiferromagnetism and d-wave superconductivity

The interplay between antiferromagnetism and d-wave superconductivity is studied in a mean-field approximation for a generic microscopic Hamiltonian with short-range repulsion and near-neighbor attraction. In the presence of competing microscopic interactions, the phase boundaries of antiferromagnetic apd superconducting states are significantly modified in some region of the doping-temperature plane. The transition between superconductivity and antiferromagnetism occurs through a phase where both order parameters coexist with a third, dynamically generated, spin-tripler amplitude. This dynamical generation of a new order parameter is not restricted to a system with antiferromagnetism and cl-wave superconductivity, but is a generic feature for fermionic Systems. The dynamically generated spin;triplet order parameter is found to be robust to variations in the mean-field Hamiltonian.