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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.
Based on the first-principle pseudopotential plane wave method, the optical properties of the bulk modulus of CuC1 and CuBr.CuI, the first-order partial derivative of pressure, the electronic structure and the refractive index of CuC1 and CuBr.CuI were calculated.The calculated results show that, The calculated values of lattice constant and bulk modulus for CuX (X = Cl, Br, I) crystals are less than the experimental ones under the generalized gradient approximation (GGA). Compared with LDA, GGA is more suitable for CuX (X = Cl, Br, I). The valence bands of all three originate from the 3d state of Cu, the conduction band partly comes from the s electron contribution of Cu and halogen, and the latter comes from the p electron contribution of halogen The calculated refractive indices of CuCl, CuBr and CuI are 1.887, 2.015 and 2.199, respectively, which are in good agreement with the results obtained from Gladstone-Dale semi-empirical relationship.