Kondo-attractive-Hubbard model for the ordering of local magnetic moments in superconductors

We consider local magnetic moments coupled to conduction electrons with on-site attraction in order to discuss the interplay between pairing and magnetic order. We probe the ground-state properties of this model on a one-dimensional lattice through pair binding energies and several correlation functions calculated by means of density-matrix renormalization group. A phase diagram is obtained (for fixed electron density 1/3) from which we infer that coexistence between magnetic order and superconductivity is robust at the expense of a continuous distortion of the magnetic arrangement of the local moments as evidenced by a strong dependence of the characteristic wave vector k(*) on the coupling constants. This allows us to understand some trends of the coexistence, such as the influence of the rare earth on k(*), as observed experimentally in the borocarbides.

Keywords

antiferromagnetic materials, binding energy, boron compounds, dysprosium compounds, ground states, holmium compounds, Hubbard model, Kondo effect, magnetic moments, nickel compounds, phase diagrams, renormalisation, spin density waves, superconducting materials, thulium compounds