几种元素掺杂二维MgCl_(2)单层的第一性原理计算

First-Principles Calculations of Several Elements Doping Two-Dimensional MgCl_(2) Monolayer

采用基于密度泛函理论的第一性原理赝势平面波方法对H,F,Al,K,Zn掺杂二维MgCl_(2)单层材料的几何结构和电子性质进行研究.结果表明:几种掺杂体系的晶体结构均有不同程度变化;由于H,Al,Zn的s态电子影响,这3种元素掺杂的MgCl_(2)在禁带中明显出现杂质能级,F和K掺杂体系的杂质能级出现在价带顶,与本征MgCl_(2)材料的5.996 eV带隙相比,H,F,Al,K,Zn掺杂体系的禁带宽度分别减小至5.665,5.903,4.409,5.802,5.199 eV;5种掺杂体系杂质原子周围的电荷均重新分布;电荷转移情况与差分电荷密度结果一致;与本征MgCl_(2)的功函数8.250 eV相比,H,F,Al,K,Zn掺杂体系的功函数分别减小至7.629,7.990,3.597,7.685,7.784 eV.

The first-principles pseudopotential plane wave method based on density functional theory was used to investigate the geometric structures and electronic properties of H,F,Zn,K,Al doped two-dimensional(2D)MgCl_(2) monolayer materials.The results show that the crystal structures of these doped systems distort in different degrees.Due to the influence of s-state electrons of H,Al and Zn,the impurity levels of doped MgCl_(2) appear in the forbidden bands,while the impurity levels of F and K doped systems appear in the valence bands.Compared with the 5.996 eV band gap of intrinsic MgCl_(2) material,the band gap widths of H,F,Al,K and Zn doped systems decrease to 5.665,5.903,4.409,5.802,5.199 eV,respectively.The charges around the impurity atoms of five doped systems are redistributed.The charge transfers are consistent with the charge density difference results.Compared with the intrinsic work function 8.250 eV of MgCl_(2),the work functions of H,F,Al,K and Zn doped systems decrease to 7.629,7.990,3.597,7.685,7.784 eV,respectively.