光折变晶体KTa_(0.5)Nb_(0.5)O_3光学特性的第一性原理研究  

First principle study on optical properties of KTa_(0.5)Nb_(0.5)O_3

作　　者：王渊旭[1] 王春雷[1] 袁敏[1] 赵明磊[1] 钟维烈[1] 

机构地区：[1]山东大学物理与微电子学院,济南250100

出　　处：《物理学报》2004年第9期3141-3145,共5页Acta Physica Sinica

基　　金：国家重点基础研究规划项目 (批准号 :G19980 614 0 8);山东大学青年科学基金资助的课题~~

摘　　要：用全电势线性缀加平面波法 (FLAPW)计算了KTa0 5Nb0 5O3四方相和立方相的光学特性 ,即介电函数虚部ε2 (ω)、光学吸收系数I(ω)和反射率R(ω) .在四方相 ,介电虚部沿a ,b轴 ,在 3,7和 2 3eV附近 ,分别有三个介电峰 .沿c轴的三个介电峰分别位于 4 ,8和 2 3eV .其中 4eV附近的介电峰非常尖锐而且高 .从 8至 1 8eV ,沿a ,b ,c轴三个方向都有许多低的介电峰 .通过对两相光学特性的对比分析发现铁电相KTa0 5Nb0We have calculated the optical properties(the imaginary part of the dielectric function ε 2(ω) ,the optical absorption coefficient I(ω) ,the reflectivity R(ω) ) of tetragonal and cubic crystals of KTa 0 5 Nb 0 5 O 3 by the full potential linearized augmented plane wave method (FLAPW).Our calculated tetragonal optical spectra show three big peaks around 3,7 and 23 eV along a and b separately.Along c ,there are three mainly peaks at 4,8,23 eV respectively,among which the one at 4 eV is sharp and high.Comparing optical properties in the tetragonal and cubic phass,we concluded that the tetragonal phase has more anisotropic optical responses.

关 键 词：铁电体 光折变晶体 平面波法 光学常量 光学参数 铌酸钽钾晶体 反射率 

分 类 号：O437[机械工程—光学工程]