Zn原子位置对ZnO晶体电子结构的影响

Effects of Zn Atomic Location on Electronic Structure of ZnO

本文基于密度泛函理论(DFT)的第一性原理方法,计算了Zn原子位置对ZnO电子结构的影响。Zn的位置变化导致ZnO晶体发生晶格畸变,使电子结构发生变化;能带结构、能态密度(DOS)、电子密度、Mulliken布居等计算结果分析表明:Zn原子位置在z轴方向改变后使得Zn—O键长缩短,Zn的3d电子与O原子的2p电子在-8.0^-0.5 eV区域的杂化作用加强,导致O原子的部分2p电子向低能方向移动,带隙展宽。

The systematic trends of structural and electronic properties of ZnO depending on the varied Zn atomic location in the z-axis were studied by the plane-wave pseudopotential density functional theory（DFT） method with the generalized gradient approximation（GGA） and Perdew Wang（1991） basis for the exchange-correlation potential.The optimized lattice parameters and equilibrium structure are in good agreement with available theoretical values and experimental data.The predicted ZnO crystal structure and properties dependence on Zn atomic sites were studied for the first time.Our results show that the ZnO lattice will be distorted as Zn atom moves to different location in the z-axis;furthermore,analysis of calculated results,comprising of energy band,density of state（DOS）,electronic density,Mulliken charge population etc.,show that the bond length of Zn—O will be decreased due to the increased Zn atomic location in the z-axis（0 to 0.1）,and in the energy range of-8.0 to-0.5 eV,the interaction seems stronger as the stronger hybridized caused by the 3d electron of Zn and 2p electron of O,as the result of the changed Zn atomic location from 0 to 0.1,the resulted partial electrons of 2p of O atom will be shifted to the lower zone and the energy gap will be broadened.