Sr2MoBO6(B=Os、Re、W)的电子结构与光学性质的第一性原理

双钙钛矿氧化物Sr₂MoBO₆(B=Os、Re、W)已被预测为具有高磁转变温度的半金属材料。本论文对Sr₂MoBO₆的电子结构和光学性质进行了第一性原理计算,并分析了二者之间的内在关系。从能带结构来看, Sr₂MoOsO₆和Sr₂MoWO₆为半金属,Sr₂MoReO₆为普通金属。B 5d与Mo 4d之间的跃迁过程使三种材料复介电函数的虚部ε₂(ω)在可见光区域均有明显的介电峰,进一步使它们都具有很宽的吸收光谱和很高的吸收系数。其中,Sr₂MoReO₆和Sr₂MoWO₆的吸收光谱横跨整个可见光区并延伸至红外波段。Sr₂MoReO₆在可见光波段的最高吸收系数为41.86×10⁴ cm^-1,其中一个吸收峰位于886 nm处;Sr₂MoWO₆的吸收峰位于780 nm处,峰值吸收系数高达41.62×10⁴ cm^-1。另外,Sr₂MoBO₆在整个可见光范围内都具有很高的反射率,Sr₂MoWO₆的反射率峰值可达到0.55。Sr₂MoBO₆对可见光的响应特性预示着其在光电子器件领域广泛的应用前景。

First-Principle Study on Electronic Structure and Optical Properties of Sr2MoBO6 (B=Os,Re,W)

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.