四面体掺杂尖晶石结构Co_(1-x)Re_xCr_2O_4(Re=Li、Na、K、Rb)的电子结构和光学性质  

The Electronic and Optical Properties of Tetrahedral Doped Co_(1-x)Re_xCr_2O_4(Re = Li, Na, K, Rb) Spinel

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,西安710048 [2]宝鸡文理学院物理与光电技术学院,宝鸡721016 [3]西北工业大学理学院,西安710072

出　　处：《无机材料学报》2015年第8期819-824,共6页Journal of Inorganic Materials

基　　金：国家自然科学基金(11204007);陕西省科技攻关计划(2014K08-17);陕西省自然科学基金项目(2012JQ1011);陕西省教育厅科学研究项目(12JK0983);宝鸡市科技攻关计划(14GYGG-5-2);宝鸡文理学院项目(YK1027;ZK14011;ZK15009)~~

摘　　要：采用基于密度泛函理论(DFT)的平面波超软赝势方法,计算了CoCr2O4及Li、Na、K和Rb四面体掺杂CoCr2O4的基态结构、电子结构和光学性质。计算结果表明:一价离子四面体掺杂都导致晶格有微小的畸变,使体系的稳定性降低,Rb掺杂的体系最稳定;电子态密度的计算结果表明:掺杂体系的导带主要有Co-3d和Cr-3d轨道电子构成,掺杂离子改变了CoCr2O4导带的电子结构,主要引起了导带Co-3d态密度峰的下移,随着掺杂浓度的增大,费米能级进入价带更深;光学性质计算表明:掺杂体系的吸收光谱发生红移,并在低能区有很强的吸收,表明掺杂能极大地提高CoCr2O4对可见光的吸收和光催化效率。The structure parameters, electronic density of states, and optical properties of Re （Re = Li, Na, K and Rb） doped tetrahedral Co-1-x）RexCr2O4（x=0.125） system were investigated by using plane-wave ultrasoft pseudopotential method with generalized gradient approximation. The obtained data indicate that monovalent ions doping results in a slight tetrahedral lattice distortion, leading to the stability of the system being reduced and the Rb doped system the most stable. The calculated electronic density of states demonstrates that the conduction bands of doping system are mainly dominated by Co-3d and Cr-3d electrons and the peak of Co-3d in conduction band shifts down when com- pared to the pure CoCr2O4. Moreover, the Fermi levels of the doping system get into the deeper valence band along with the doping concentration increases. Finally, the doped systems present a red shift phenomenon and a strong ab- sorption in the low energy region according to the absorption spectral calculations, suggesting that doping system can greatly improve the absorption and photo catalytic efficiency of visible light for CoCr2O4.

关 键 词：尖晶石结构CoCr2O4 密度泛函理论 电子结构 光学性质 

分 类 号：TQ626[化学工程—精细化工] TQ630