Co掺杂MgF_2电子结构和光学特性的第一性原理研究

First-principles study of electrical structures and optical properties of Co:MgF_2 crystal

基于密度泛函理论(DFT)的第一性原理平面波超软赝势方法,计算了Co掺杂MgF2晶体的几何结构、电子结构和光学性质.结果表明,Co掺杂导致MgF2晶体结构畸变,可能发生一种类四方和斜方型结构相变.由于Co原子的加入,体系的禁带宽度减小,可观察到半导体—金属性转变.计算也表明,Co掺杂对静态介电常数和光吸收系数有重要调制作用,所得结果与最近实验测量很好相符,揭示了Co:MgF2体系在光学元器件方面的潜在应用.

Based on the density functional theory,the geometries,electrical structures and optical properties of Co-doped MgF2 system （Co：MgF2） are studied by first-principles ultra-soft pseudopotential plane-wave approach. With Co-doping increasing,a tetragonal-rhombic structural transition is obtained in Co：MgF2. The band gap decreases with increasing Co-doping,and a semiconductor-conductor transition is observed. Also,the calculations show that the static dielectric constant and the absorption coefficient can be remarkably modulated by Co-doping,indicating the potential applications of Co：MgF2 optical system.