Theoretical prediction of half-metallic materials in double perovskites Sr2Cr(Co)B′O6 (B′=Y, La, Zr, and Hf) and Sr2V(Fe)B′O6 (B′=Zr and Hf)

Abstract

Abstract In this work, we have investigated stable half-metallic materials of the double perovskites Sr 2 BB′ O 6: Sr 2 Cr(Co) B′ O 6 ( B′ = Y, La, Zr and Hf) and Sr 2 V(Fe) B′ O 6 ( B′ = Zr and Hf). Based on the density functional theory, the calculations are conducted with full structural optimization. Generalized gradient approximation (GGA) and additional correlation effect (GGA+ U ) are used. In the GGA+ U scheme, the energy gaps of Sr 2 CoZrO 6 are opened in both spin-channels and become ferromagnetic insulators (FM-Is); Sr 2 CoZrO 6 , Sr 2 CoHfO 6 , Sr 2 FeZrO 6 , and Sr 2 FeHfO 6 transfer from low-spin state to high-spin state. The half metallicity are attributed by the double-exchange interaction mechanism via the B ( t 2g )–O(2 p )– B’ ( t 2g ) π-bounding.