A Coulomb gas approach to the anisotropic one-dimensional Kondo lattice   model at arbitrary filling
  We establish a mapping of a general spin-fermion system in one dimension into a classical generalized Coulomb gas. This mapping allows a renormalization group treatment of the anisotropic Kondo chain both at and away from half-filling. We find that the phase diagram contains regions of paramagnetism, partial and full ferromagnetic order. We also use the method to analyze the phases of the Ising-Kondo chain. 
E. Novais, E. Miranda, A. H. Castro Neto, and G. G. Cabrera