Eu掺杂MgO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 for Eu-doped MgO

为探究稀土元素掺杂对金属氧化物MgO晶体材料电子结构和光学性质的影响,采用基于密度泛函理论的第一性原理赝势平面波方法计算Eu原子掺杂MgO晶体的几何结构、能带结构、态密度和光学性质.计算结果表明:掺杂后体系的带隙宽度减小,费米面向导带偏移,属于直接禁带半导体.掺杂稀土元素对体系的静态介电常数、晶体反射率、光吸收系数、折射率和能量损失函数具有重要的调制作用.掺杂前后晶体的光学性质,包括晶体吸收系数、反射率、折射率和能量损失函数的曲线峰值均较掺杂前的峰值有所降低,且曲线整体有向低能方向移动的趋势.

In order to explore the effect of doping rare earth element on the electronic structure and optical properties of metal oxide MgO crystal materials, the geometric structure, band structure, density of states and optical properties of Eu atom doped MgO crystal was calculated by the first principles pseudo potential plane wave method based on the density functional theory. The results show that the band gap width of the doped system which belongs to the direct band gap semiconductor is decreased, and its Fermi surface oriented to the conduction band. Doping rare earth elements have important modulation effects on the static dielectric constant, crystal reflectivity, optical absorption coefficient, refractive index and energy loss function of the whole system. The optical properties of the doped crystals, including the curve peak values of the crystal absorption coefficient, reflectivity, refractive index and energy loss function are lower than the peak values before doping, and the curves of the optical properties have a tendency to move towards the low energy direction.