Mg, Sr掺杂CaF2电子结构及光学性质的第一性原理研究

采用基于密度泛函理论(DFT)的第一性原理方法对纯CaF2晶体和Mg、Sr掺杂CaF2体系的晶体结构、电学以及光学性质进行了详细的对比研究, 结果表明: 与纯CaF2晶体相比, 掺杂体系的带隙变窄且形成新的态密度峰, 费米面附近出现F与Mg、Sr原子间轨道杂化加强现象. 另外, 掺杂体系仅表现出介电性质, 其对紫外光的吸收强度大大减弱, 而Ca7SrF16掺杂体系在25.44 eV处产生新的小吸收峰. CaF2晶体掺入Mg、Sr原子后, 体系在紫外光区的消光系数减小且对紫外光的透过率增大. 此外, 掺杂体系的反射谱峰和损失函数峰均发生红移且峰值显著降低.

First-principles calculations of the electronic structures and optical properties of Mg- and Sr-doped CaF2

Based on the density functional theory (DFT), the first-principles methods are used to study and compare the electronic structures and optical properties of Mg-, Sr-doped CaF2 systems with those of CaF2 bulk in detail. In contrast to CaF2 bulk, the band gaps of doped systems become narrower and the new peaks of density states appear. The orbital interactions between Mg, Sr atoms and Ca atom are enhanced near the Fermi level, besides, the doped systems all show single dielectric properties and their absorption coefficients for ultraviolet light are reduced greatly, for Ca7SrF16 system, there is a small absorption peak at 25.44 eV. Compared with CaF2 bulk, doped systems have much lower extinction coefficients and much higher light transmittance in the ultraviolet region. In addition, their reflection and loss peaks all display red shift and the peak value reduce. Keywords: density functional theory, electronic structure, optical property, dope