Superconductivity driven by magnetic instability in CeCu2Si2

Abstract

The coexistent of superconductivity (SC) with antiferromagnetism (AFM) and ferromagnetism (FM) as U ?? is studied in CeCu₂Si₂ on application of the Exact Diagonalization technique to the Single site Impurity Anderson Model and the Periodic Anderson Model. The results obtained show that magnetic instability is the key to understanding superconductivity in Heavy Fermion compounds as increasing the onsite coulomb repulsion, U, suppresses all ferromagnetic tendencies and enhances superconductivity. The results obtained here is in qualitative agreement with the inelastic neutron scattering experimental results obtained by Stockert et al (2011) on increasing the copper content in CeCu₂Si₂. U in this theoretical study behaves as Cu in the inelastic neutron scattering experiment.

Keywords: Heavy fermion, antiferromagnetism, superconductivity, ferromagnetism, singlet state energy, triplet state energy.