Electronic structure of half-metallic double perovskites

We present the self-interaction corrected local spin density (SIC-LSD) electronic structure and total energy calculations, leading also to Fe valencies of the ground state configurations, for the double perovskites such as Sr2FeMoO6, Ba2FeMoO6, Ca2FeMoO6, and Ca2FeReO6. We conclude that the Fe and Mo (or Re) spin magnetic moments are anti-parallel aligned, and the magnitude of the hybridization induced moment on Mo does not vary much between the different compounds. The hybridization spin magnetic moment on Re is of the order of -1.1mu(B), while that on Mo is about -0.4mu(B), independently of the alkaline earth element. Also the electronic structure of all the compounds studied is very similar, with a well defined gap in the majority spin component and metallic density of states for the minority spin component, with highly hybridized Fe, Mo (or Re), and oxygen bands. All insulating solutions found for Ca2FeReO6 are energetically unfavorable with respect to the calculated half-metallic ground state.