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首先采用基于密度泛函理论(DFT)框架下广义梯度近似平面波超软赝势法(包括PBE、PBESOL、PW91、RPBE、WC)对尖晶石型ZnGa2O4的结构进行了优化,得到和实验值最接近晶格常数a0=0.837 8 nm;然后在结构优化的基础上采用GGA-WC计算ZnGa2O4的电子结构和光学性质。结果表明,ZnGa2O4为间接带隙复合氧化物,带隙宽为2.335 eV;ZnGa2O4的静态介电常数为3.45,静态折射率为1.85,介电函数吸收边位于4.0 eV附近;ZnGa2O4的反射系数在19.3 eV附近取得最大值,吸收系数在11.0 eV~17.5eV间取值均较大,电子能量损失谱的共振峰在20.5 eV处,并与此能量时反射系数R(ω)的陡降相对应。
Firstly, the structure of spinel-type ZnGa2O4 was optimized by the super-soft pseudopotential method (including PBE, PBESOL, PW91, RPBE and WC) based on the density functional theory (DFT) Close to the lattice constant a0 = 0.837 8 nm. Then the electronic structure and optical properties of ZnGa2O4 were calculated by GGA-WC based on the structural optimization. The results show that ZnGa2O4 is an indirect bandgap compound oxide with a bandgap of 2.335 eV. The quaternary dielectric constant of ZnGa2O4 is 3.45, the quasi-refractive index is 1.85, the dielectric absorption edge is located near 4.0 eV, and the reflection coefficient of ZnGa2O4 is 19.3 eV, and the absorption coefficient was large between 11.0 eV and 17.5 eV. The resonance peak of the electron energy loss spectrum was at 20.5 eV, corresponding to the steep fall of the reflection coefficient R (ω) at this energy.