Co掺杂ZnO的电子结构及磁性质

The electronic structure and magnetic properties of Co doped ZnO

本论文选择目前研究较少的ZnO立方闪锌矿结构,基于密度泛涵理论的超软赝势法(USPP),结合局域密度近似(LDA),应用Material Studio5.5软件采用LDA+U方法进行计算。计算本征态下ZnO(1*1*1,2*1*1,2*2*1不同超晶胞)的电子态密度,能带结构,分析得出本征态ZnO的总态密度价带主要由Zn的3d和O的2p轨道电子组成,验证了靠近费米能级附近处的价带。计算Co替代立方结构ZnO的Zn的态密度和能带结构,并与本征态下ZnO的态密度和能带结构做比较,发现掺杂后电子态密度无较大变化,导带在Co掺杂浓度为25%时最宽即导电性最强,禁带宽度在掺杂后变窄。由实验得出的Zn1-xCoxO的磁化强度随温度和磁场强度的变化,绘制不同掺杂浓度样品的M-T和M-H曲线,讨论材料的磁化性质,并结合电子结构计算结果。

This paper choose the ZnO cubic zinc blende structure, based on ultra soft pseudopotential method density functional theory(USPP), using the local density approximation(LDA), the application of Material Studio5.5 software is calculated with LDA+U method. Calculating the eigenstates of ZnO(1*1*1, 2*1*1, 2*2*1 supercell) of the electronic density of States, energy band structure, analyzes the total density of states of valence band eigenstates of ZnO is mainly composed of 2p orbital electron Zn 3D and the composition of O, near the Fermi level is verified in the vicinity of the valence band. The density of states calculated Co alternative cubic structure of ZnO Zn and the band structure, and density of eigenstates of the ZnO and the band structure is compared, found that after doping electronic density of states have no obvious change, the conduction band in the Co doping concentration is 25% of the width of the conductive strongest, narrow band width in doping. By magnetization experiments of Zn1-xCoxO with temperature and the variation of magnetic field intensity, drawing samples doped with different concentrations of M-T and M-H curve, discusses the magnetic properties of materials, the calculation results combined with the electronic structure.