Abstract: Double perovskite oxides Sr₂MoBO₆ (B=Os,Re,W) have been predicted to be half metals with high magnetic ordering temperature. In this work, the electronic structure and optical properties of Sr₂MoBO₆ were calculated by first-principles method, and the intrinsic relationships between them were also discussed. From the energy band structure, Sr₂MoOsO₆ and Sr₂MoWO₆ are half metals, and Sr₂MoReO₆ is a normal metal. The imaginary part ε₂(ω) of the complex dielectric function of Sr₂MoBO₆ all have obvious dielectric peaks in the visible region due to the transition process between B 5d and Mo 4d. Further, the three compounds all have a wide absorption spectrum and a high absorption coefficient. Among them, the absorption spectra of Sr₂MoReO₆ and Sr₂MoWO₆ stretch across the whole visible region and even extend to the infrared band. The highest absorption coefficient of Sr₂MoReO₆ in the visible region is 41.86×10⁴ cm^-1, and one of the absorption peaks is located at 886 nm. The absorption peak of Sr₂MoWO₆ is at 780 nm and the peak absorption coefficient is 41.62×10⁴ cm^-1. In addition, Sr₂MoBO₆ have high reflectivity in the whole range of visible region. The peak reflectivity of Sr₂MoWO₆ can reach up to 0.55. The response of Sr₂MoBO₆ to visible light indicates that they have a wide application prospect in the field of optoelectronic devices.

Key words: double perovskite, electronic structure, optical property, dielectric function, absorption coefficient, first-principle