Na+对尖晶石结构Co(1-x)NaxCr2O4电子结构及光学性质的影响Na+对尖晶石结构Co(1-x)NaxCr2O4电子结构及光学性质的影响.doc

·研究论文· Na+对尖晶石结构Co(1-x)NaxCr2O4电子结构及光学性质的影响 杨志怀*,1,2 张云鹏1 张美光2 许强2 张亚妮2 张蓉3 (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 物理与信息技术系, 宝鸡 721016 ) (3西北工业大学 理学院 西安 710072 ) 摘要 采用基于密度泛函理论(DFT)的平面波超软赝势法, 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+掺杂浓度为x=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+掺杂浓度增加（x=0.0, 0.125, 0.25, 0.375, 0.5, 0.625）,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.f Electronic Structure and Optical Properties of Spinel Structure Co(1-x)NaxCr2O4 With Na+ YANG Zhihuai*,1，2 ZHANG Yunpeng1 ZHANG Mei-guang2 XU Qiang2 ZHANG Ya-ni2 ZHANG Rong3 (1 School of Materials Science and Engineering, Xian University of Technology, Xian 710048, China)(2 Department of Physics and Information Technology, BaoJi University of Arts and Sciences, Baoji 721016, China) (3 Science College, Northwestern Polytechnical University, Xian 710072, China) Abstract 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)NaxCr2O4 system were fully investigated. The results indicated that Na+ is easier to enter tetrahedral sites (Co) in comparison with octahedral sites (Cr) with concentration of x=0.125 for Na+. With the increasing of doping concentration 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 shifted to red in the low energy region, and a strong absorption in the low energy region thus can be obtained. This indicates that the doping Na+ can substantially improve the absorption of visible light and enhance cata