On the splitting of the lower band of charged elementary excitations of a two-dimensional antiferromagnet

A spin-polaron approach is developed on the basis of a generalized Kondo lattice model for a two-dimensional antiferromagnet (CuO2 plane model). This approach makes it possible to describe the splitting of polaron bands of carriers both in the presence of long-range magnetic order (T=0) and for a finite spin-correlation length (T not equal 0) and also can account for the strong deviation from the Luttinger theorem and the shadow-bands effect at both zero and finite temperatures. (C) 1998 American Institute of Physics. [S0021-3640(98)00717-8].