Na^+对尖晶石结构Co_((1-x))Na_xCr_2O_4电子结构及光学性质的影响  

Effect of Na^+ on Electronic Structure and Optical Properties of Spinel Structure Co_((1-x))Na_xCr_2O_4

作　　者：杨志怀[1,2] 张云鹏[1] 张美光[2] 许强[2] 张亚妮[2] 张蓉[3] 

机构地区：[1]西安理工大学材料科学与工程学院,陕西西安710048 [2]宝鸡文理学院物理与信息技术系,陕西宝鸡721016 [3]西北工业大学理学院,陕西西安710072

出　　处：《光学学报》2014年第11期34-43,共10页Acta Optica Sinica

基　　金：陕西省重点学科建设专项资金;陕西省自然基金(2012JQ1011);陕西省教育厅科学研究项目(12JK0983;2014KW07-01;2014K08-17);宝鸡文理学院重点项目(YK1027;ZK12047)

摘　　要：采用基于密度泛函理论的平面波超软赝势法,系统研究了Na+四面体掺杂Co(1-x)NaxCr2O4体系的基态结构参数、能带结构、电子态密度、磁矩和光学性质。当Na+掺杂离子数分数x为0.125时,计算结果表明Na+四面体掺杂(Co位)比八面体掺杂(Cr位)容易进行。对Na+四面体掺杂体系Co(1-x)NaxCr2O4,计算发现,随着Na+掺杂离子数分数增加,体系的晶格参数逐渐增大,晶胞的磁矩和禁带宽度均减小。同时,费米能级进入价带部分更深。此外,光学性质的结果显示Na+可以使CoCr2O4的吸收光谱发生红移,并在低能区有很强的吸收,表明Na+能极大地提高CoCr2O4对可见光的吸收和光催化效率。By using the plane-wave ultrasoft pseudopotential method within the generalized gradient approximation, the structure parameters, band structure, electronic density of states, magnetic moment, and optical properties of Na^＋ doped tetrahedral Co（1-x）NaxCr2O system are fully investigated. The results indicate that Na＋ is easier to enter tetrahedral sites （Co） in comparison with octahedral sites （Cr） with ion doping fraction of 0. 125 for Na^＋ . With the increase of ion doping fraction of Na^＋ in Co（1-x）NaxCr2O4 system, the lattice parameters become larger as in the usual case, on the contrary, the magnetic moment and band gap become smaller. Meanwhile, the Fermi level moves deeper into the valence band region. In addition, the absorption spectra of Co（1-x）NaxCr2O4 shift to red in the low energy region, and a strong absorption in the low energy region is obtained. This indicates that the doping Na^＋ can substantially improve the absorption of visible light and enhance catalytic efficiency of CoCr2 O4.

关 键 词：原子与分子物理 密度泛函理论 第一性原理 电子结构 光学性质 尖晶石结构CoCr2O4 

分 类 号：O436.2[机械工程—光学工程] O469[理学—光学]