Si_3P_4和Ge_3P_4电子结构及光学性质的第一性原理研究

First Principle Study on Electronic Structure and Optical Properties of Si_3P_4 and Ge_3P_4

采用基于密度泛函理论的广义梯度近似(GGA),计算了赝立方结构的Si3P4和Ge3P4的基态稳定结构,以及它们的电子结构和光学性质。计算结果表明:Si3P4和Ge3P4均为间接带隙半导体,Si-P键及Ge-P键成键方式为共价键;Si3P4和Ge3P4均具有较大的静态介电常数;两者相比较而言,Ge3P4的反射率、折射率及吸收系数在数值上更大。从Si3P4和Ge3P4的能量损失函数中可知仅有外层电子参与了光学跃迁。计算结果为这两种材料的潜在应用提供了理论依据。

The stability of the ground-state structure of Si3V4 and Ge3 P4 was well studied by using the first principles method based on density functional theory generalized gradient approximation （GGA）. The lattice constant under steady-state was obtained. Furthermore, the electronic structure and absorption properties were also evaluated by the calculations. The results indicate that both Si3P4 and Ge3P4 are narrow indirect gap semiconductor, the bonding mode of Si-P and Ge-P are covalent bond. Compared with Si3N4, the Si3 P4 and Ge3 P4 show relatively larger static dielectric function constant, and the reflectivity and refractive index of Ge3 P4 are larger than those of Si3P4. According to the energy losing function of Si3 P4 and Ge3P4, it can be concluded that only out shell electrons are involved in the optical transition.