Spin polaron approach to superconductivity

Superconducting pairing is considered for a two-dimensional system with strong correlation between the carrier subsystem and the subsystem of localized spins. The Kondo lattice model is analyzed for the case where spin polarons are the elementary excitations. It is shown that taking into account only the anomalous Green's functions for bare holes is insufficient for superconducting pairing to occur; it arises only after the introduction of the anomalous Green's functions for spin-polaron operators.