伽马CuX(X=Cl,Br,I)的电子结构和光学性质的第一性原理计算

First principles calculation of electronic structures and optical properties for γ-CuX(X = Cl,Br,I)

基于第一性原理赝势平面波方法对伽马晶体CuC1,CuBr.CuI的体模量、体模量对压强的一阶偏导数、电子结构、折射率等光学性质进行了计算.计算结果表明,广义梯度近似(GGA)下CuX(X=C1,Br,I)晶体的晶格常数与体模量的计算值与实验相差较小.与局域密度近似(LDA)相比,GGA更适合于CuX(X=C1,Br,I)晶体的计算.这三者的价带都来源于Cu的3d态,导带部分主要来自Cu和卤素的s电子贡献,很少部分来自卤素的p电子贡献.计算得到CuCl,CuBr,CuI的折射率分别为1.887,2.015,2.199,与应用Gladstone-Dale半经验关系得到的结果符合得很好.

We use first-principles calculation with pseudo-potential and plane wave method to study the bulk meduli,electronic structures and optical properties of copper halides CuX（X = Cl,Br,I）.A comparison of the calculation results with the available experimental results show that it is more suitable using the generalized gradient approximation to study these properties than using the local density approximation.The results show that valence bands of CuX（X = Cl,Br,I） are dominated by the d bands of Cu.Conduction bands are mainly from s bands of Cu and halide atoms,as well as from p bands of halide atoms.The calculated refractive indices of CuX（X = CI, Br,I） are 1.887,2.015,and 2.199,respectively.These results are in good agreement with the those calculated from the Gladstone-Dale relationship.