We show that an interplay of double exchange and impurity randomness canexplain the competition between metal-ferromagnetic and insulating chargeordered states in doped manganites. The double exchange is simplified in theIsing type, whereas the randomness is modeled by the Falicov-Kimball binarydistribution. The combined model is considered in a framework of dynamicalmean-field theory. Using the Kubo-Greenwood formalism, the transportcoefficients are explicitly expressed in terms of single particle spectralfunctions. Dividing the system into two sublattices we have pointed out adirect calculation to the checkerboard charge order parameter and themagnetizations. Numerical results show us that the checkerboard charge ordercan settle inside the ferromagnetic state at low temperature. Aninsulator-metal transition is also found at the point of the checkerboardcharge order-ferromagnetic transition.
展开▼
