Island phases and charge order in two-dimensional manganites - art. no. 024422

The ferromagnetic Kondo lattice model with an antiferromagnetic interaction between localized spins is a minimal description of the competing kinetic (t) and magnetic (K) energy terms which generate the rich physics of mangan ite systems. Motivated by the discovery in one dimension of homogeneous "is land phases." we consider the possibility of analogous phases in higher dim ensions. We characterize the phases present at commensurate fillings, and c onsider in detail the effects of phase separation in all filling and parame ter regimes. We deduce that island and flux phases are stable for intermedi ate values of Kit at the commensurate fillings n=1/4, 1/3, 3/8, and 1/2. We discuss the connection of these results to the charge and magnetic orderin g observed in a wide variety of manganite compounds.