Spin Polarons in Two Dimensional Antiferromagnetic Systems - are they Well Defined Quasiparticles?

The theory of spin-polarons in two-dimensional antiferromagnetic spin 1/2 systems described in terms of the t - J model is reviewed shortly. Then the problem of two interacting spin-polarons is discussed in the self consistent Born approximation. It appears that for realistic values of the parameter J/t of the model repulsive interaction between spin-polarons prevails so there are no bound states.