钼酸镉晶体电子结构和光学性质的第一性原理研究

First Principles Study on Electronic Structure and Optical Properties of CdMoO_4

本文利用了基于密度泛函理论的第一性原理和平面波赝势方法计算了CdMoO4晶体的电子结构和光学性质。分别采用了广义梯度近似(GGA)和局域密度近似(LDA)对晶胞参数进行优化,得到了最稳定状态下的晶胞参数。在优化结构的基础上得到了两种近似下的能带结构,电子态密度和介电函数。能带结构表明CdMoO4的价带顶和导带底均在Γ点,直接带隙分别为2.342 eV(GGA),2.241 eV(LDA)。电子态密度计算结果说明Mo4d和O2p轨道之间强烈杂化形成Mo-O共价键,且其键性强于Cd-O键。计算得到的介电函数实部与虚部和Abraham等用WIEN97软件计算的结果吻合得较好。

The electronic structure and optical properties of CdMoO4 crystal are investigated within the framework of density functional theory and projector-augmented-wave methods. The crystal structure is optimized using both the generalized gradient approximation （GGA） and the local-density approximation （LDA） respectively, and the crystal cell parameters in the most stable state are obtained. Based on the optimized geometries, the band structure, electron density and dielectric function are calculated in the mentioned two approximations. The band structure shows that the valence band maximum and the conduction band minimum are both located at F point, and the direct gaps are 2.342 eV （GGA） ,2.241 eV（LDA）. The densities of states indicate that Mo4d and O2p states form a strong Mo-O covalent bond, and the bonding strength is higher than Cd-O bond. The calculated dielectric function is in good agreement with other calculated result using WIEN97 software by Abraham et al.