ZnS掺Mn^(2+)电子结构和光学性质的第一性原理计算

Electronic structures and optical properties of Mn^(2+)-doped ZnS by first-principles calculation

在广义梯度近似下,利用平面波赝势对ZnS(闪锌矿,F-43m)和Mn^(2+)掺杂的ZnS超晶胞的电子态密度、原子间电子云重叠布局数和光学性质等进行了自恰计算.自旋极化的计算结果显示,掺入Mn^(2+)离子后态密度整体向低能方向移动,在禁带中出现了由Mn 3d、Zn3d与S 3p组成的新态.电子云重叠布局分析了掺杂前后价键性质的变化,解释了磁性离子Mn^(2+)导致Zn和S出现不对称的自旋向上和自旋向下态的机理.复介电系数谱图向高能方向迁移,并且在0到2.7 eV范围内出现一个新的尖峰,利用晶体场理论和态密度,对改介电峰进行了指认,为研究此类材料光学性质提供了一定理论依据.

The electronic structures and optical properties of ZnS (zinc blende,F - 43m) and Mn^(2+)-doped ZnS (ZnS:Mn^(2+)) have been investigated using plane-wave pseudopotential method with Generalized Gradient Approximation(GGA). The spin-polarized density of states (DOS) indicate that after introducing Mn^(2+) ion, the host states shift to lower energy level, and a new state constructed by Mn 3d states,Zn 3d states and S 3p spin-down states occurs in the band gap of ZnS. The mechanisms of the splitting spin-up and spin-down states of Zn and S in ZnS:Mn^(2+) are analyzed by the electron populations . There is an additional peak at the region of 0 to 2. 7 eV in the imaginary part of dielectric function spectra,and the host peak shifts a little to the higher energy region. Furthermore,the new peak is recognized in terms of the crystal filed theory and the electronic structures.