Metal-insulator transition in the double perovskites - art. no. 092414

We construct an effective Hamiltonian for the motion of electrons among the transition-metal ions of ordered double perovskites like Sr2FeMoO6, in whi ch strong intra-atomic Coulomb repulsion U is present in only one of the in equivalent transition metal sites. Using a slave-boson formalism, we constr uct a phase diagram that describes a charge-transfer transition between ins ulating and metallic behavior as the parameters of the model are changed. T he parameters for Sr2FeMoO6 are estimated from first-principles calculation s and a transition to the insulating state with negative pressure is obtain ed.