Spin density waves and superconductivity in strongly correlated electron systems

Abstract

A special diagram technique recently proposed for strongly correlated electron systems is used to study the peculiarities of a spin-density-wave (SDW) in competition with superconductivity. This method allows to formulate the Dyson equations for the renormalized electron propagators of the coexisting phases of SDW antiferromagnetism and superconductivity. We find the surprising result that triplet supercondctivity appears provided that we have coexistence of singlet superconductivity and SDW antiferromagnetism. In many investigations of the conditions, in which the superconducting state at the high temperatures arises, the exclusive role is given to the strong Coulomb interactions of the electrons in the system. The Coulomb interactions can also be the cause of the appearance of the spin-density-wave (SDW) state. The aim of the present paper is to investigate the influence of this interaction on the competition of the above mentioned states.