First Principles Study Of Doped Lithium Niobate Crystal Electronic Structure And Optical Properties

的电子结构和光学性质。分析结果表明,双掺杂引入了位置不同的两个杂质能级,Mn:Fe:LiNbO₃晶体中Fe杂质能级为深能级,Mn杂质能级为浅能级；Mn:Ru:LiNbO₃晶体中Ru杂质能级为深能级,Mn杂质能级为浅能级Fe:Ru:LiNbO₃晶体中Ru杂质能级为深能级,Fe杂质能级为浅能级。通过吸收谱的分析,得出双掺杂在可见光区域吸收率明显提高。三种晶体在可见光区域都有明显的吸收峰出现,并且它们的位置与实验结果相符的很好。晶体在低能区域产生吸收峰说明深浅能级的电子结构发挥了作用。 semiconductor. The valent band is contributed by O2p, while the conduct band iscontributed by Nb 4d. There are covalent bonds between them. The O is the acceptor of electrons, while the Nb is the donor of electrons. It shows obvious anisotropy inLiNbO₃ along different polarized directions. Its transmittance is well in visible range.And the dielectric function, loss function, reflectivity and absorption had closely relation with the transition of different atom orbit.(2) The electronic structure and optical properties of Mn:LiNbO₃, Fe:LiNbO₃and Ru:LiNbO₃ were calculated. There was doping state at OeV which wascontributed by the d electrons of Mn, Fe and Ru. Doping has reduced the energy of the transition of different atom orbit and the electron orbit. The highest occupied orbitis not O2p, but the d of Mn, Fe and Ru. The dopant is the acceptor and donor ofelectrons. The loss function of Fe:LiNbO₃ is increased, the efficiency of holographicdata storage will be reduced. The optical properties of three kind of crystal changed in the visible range, and there are absorption peaks in this range. It's benefit to the holographic data storage.(3) The electronic structure and optical properties of Mn:Fe:LiNbO₃,Mn:Ru:LiNbO₃ and Fe:Ru:LiNbO₃ were calculated. There are different doping states in the crystal. Mn was shallow center and Fe was deep center of Mn:Fe:LiNbO₃. Mn was the shallow center and Ru was the deep center ofMn:Ru:LiNbO₃.Fe was the shallow center and Ru was the deep center ofFe:Ru:LiNbO₃. The absorption of double-doped LiNbO₃ had increased drasticallyin visible range. The peaks of absorption were in correspondence with experimentalresults. The structure of shallow center and deep center produced the peaks ofabsorption.