【摘要】 基于密度泛函理论(Density functional theory, DFT)第一性原理平面波赝势方法,分别采用广义梯度近似(Generalized gradient approximation, GGA)与模守恒(norm-conserving)赝势配合、局域密度近似(Local-density approximation, LDA)与超软(Ultrasoft)赝势配合,对闪锌矿AlN与纤锌矿AlN电子结构和光学性质进行了计算与分析。对比了两种方法得出的两种结构AlN的晶格常数、带隙宽度、反射率、折射率以及吸收系数。结果表明:两种方法中LDA的带隙值误差小且更符合实验值;使用GGA计算的纤锌矿AlN的光学性质更接近实验值;而使用LDA计算的闪锌矿AlN的光学性质更接近实验值。更多还原

【Abstract】 With first-principles density functional theory(DFT) based on plane-wave pseudopotential method, we have calculated and analyzed the electronic structure and optical properties of wurtzite AlN and sphalerite AlN. In computational detail, generalized gradient approximation(GGA) works with Norm-conserving pseudopotential and local-density approximation(LDA) works with Ultrasoft pseudopotential, respectively. The lattice constant, band gap width, reflectance, refractive index and absorption coefficient of the two structures AlN obtained by the two methods are analyzed and compared. The comparison results show that LDA’s band gap error of two methods is smaller and more consistent with the experimental values, and the calculated optical properties of wurtzite AlN show that GGA is closer to the experimental value, for the optical properties of sphalerite AlN, LDA is closer to the experimental value.更多还原