不同位置的Mn掺杂对ZnO量子点的电磁特性影响

Influence of Mn doping at different positions on electronic and magnetic properties of ZnO quantum dot

采用基于态密度泛函理论的第一性原理赝势法,分析了直径为1.2 nm的ZnO量子点体系(Zn_(45)O_(45)H_(72),并经H钝化)在中心、中间、表面三种不同位置Mn掺杂情况下的晶体结构、能带结构、态密度分布和磁性.模拟结果表明:中间位置掺杂时,体系的结合能最低,同时导电性能最好;中心位置掺杂略劣于中间位置掺杂;而表面位置掺杂时,结合能明显偏高,同时导电性能明显减弱.在磁性方面,随着掺杂位置变化,体系中各原子的总磁矩和磁矩分布会发生明显变化,但体系的总磁矩基本不变.

The crystal structures,band structures,densities of states and magnetisms of ZnO quantum dot systems(Zn_(45)O_(45)H_(72),passivated by H)with diameter of 1.2 nm and Mn doping at the center,middle and surface positions are analyzed by the first principles pseudopotential method based on the density of states functional theory.The results show that the binding energy is the lowest and the conductivity is the best when doping in the middle position;the doping in the center is slightly worse than that in the middle;when doping on the surface,the binding energy is higher and the conductivity is weakened.In terms of magnetism,with the change of doping position,the total magnetic moment and the distribution of magnetic moment of each atom in the system will change obviously,but the total magnetic moment of the system is basically unchanged.