本征空位缺陷对ZnO:Mn体系电子特性及磁性的影响

本文采用基于密度泛函理论的第一性原理赝势法,分析了ZnO:Mn掺杂体系中本征空位缺陷V_(Zn)和V_O分别出现在相对Mn为近邻、次近邻、远次近邻位置时体系的晶体结构、能带分布、态密度和磁性.结果表明:ZnO:Mn体系中V_(Zn)比V_O更容易产生,且两种缺陷均更容易在Mn的近邻位置形成.其中V_(Zn)的出现没有明显改变ZnO:Mn体系的带隙,然而会使体系的导电性增加,且V_(Zn)与Mn的距离越远,导电性越强.同时,V_(Zn)减弱了体系的磁性,但与V_(Zn)的位置无关. V_O的出现会使体系带隙变宽,且电导率显著低于无缺陷ZnO:Mn体系,但是其导电性会随着V_O与Mn的距离变远而增强.同时,V_O的出现不会影响体系原来的磁性.

Influence of intrinsic vacancy defects on electronic properties and magnetic properties of ZnO: Mn system

In this paper, the first-principles calculations based on Density Functional Theory (DFT) were performed to analyze the effect of the sites of intrinsic vacancy defects VZn and VO on energy band distribution, density of states and magnetic properties of ZnO: Mn doping systems. In the ZnO: Mn supercell, the sites of vacancy defects VZn and VO are set as the nearest neighbor, next nearest neighbor and far nearest neighbor relative to Mn site, respectively. The results indicated that VZn is easier to be produced than VO in ZnO: Mn system, and the both kinds of defects are more likely to be generated in the nearest neighbor of Mn. Meanwhile, there is no significant change of bandgap for VZn in the ZnO: Mn system, but the conductivity will increase comparison with the defect-free system. The farther distance between VZn and Mn, the stronger the conductivity of the system. However, regardless of the site of VZn, the introduction of VZn will weaken the magnetics of the system. Contrary to VZn, the introduction of VO will widen the bandgap and decrease the conductivity of ZnO: Mn system. The farther distance between VO and Mn, the stronger the conductivity of the system. However, it is still lower than that of the ZnO: Mn system. Furthermore, there is no effect on the magnetics of the system for the introduction of VO.