单层二硫化钼光学性质的第一性原理计算

Abstract

采用基于密度泛函理论的第一性原理方法计算了单层和体材料二硫化钼（MoS2）的电子能带结构及光学性质.在能带结构计算的基础上,计算了单层和体材料MoS2的介电函数虚部及实部,并导出了单层MoS2的能量损失谱、吸收系数、反射率、折射率和消光系数等.同时给出了体材料及单层MoS2介电函数图像中各峰值与对应的能带带间跃迁之间的关系.所得结果与实验结果及现有的理论结果相符合.The first-principles method based on the density functional theory has been used to calculate the electronic band structures and the optical properties of monolayer and bulk MoS₂.Based on calculated band structures,imaginary and real parts of the dielectric functions are determined.The energy loss spectrum,the absorption coefficient,the reflectivity,the refractive and the extinction coefficient are then calculated on the basis of complex dielectric functions.The relationship between peaks in the dielectric function pictures and the inter-bands transitions in the calculated band structures are pointed out,for both the monolayer and bulk MoS₂.Our calculation results are in good agreements with available experimental data and previous theoretic results.