Electronic and Optical Properties of KNbO_3,NaNbO_3 and K_(0.5) Na_(0.5) NbO_3 in Paraelectric Cubic Phase:a Comparative First-principles Study  

作　　者：周树兰 赵显 江向平 韩晓东 

机构地区：[1]Department of Material Science and Engineering,Jingdezhen Ceramics Institute,Key Laboratory of Advanced Ceramic Material of Jiangxi Province [2]State Key Laboratory of Crystal Material,Institute of Crystal Material,Shandong University

出　　处：《Chinese Journal of Structural Chemistry》2012年第8期1095-1104,共10页结构化学（英文）

基　　金：Supported by the National Natural Science Foundation of China (Nos. 50862005,51062005,91022034 and 91022027);the Jiangxi Natural Science Foundation and Cooperative Project (Nos. 2008GZC000,2009JX02060,2010GQW0038 and [2008]212);Foundation of Jiangxi Educational Committee (GJJ11204);the Jiangxi Colleges and Universities "Advanced Ceramics" scientific and technological innovation team

摘　　要：The structural,electronic and optical properties of KNbO 3 （KN）,NaNbO3（NN）and K05 Na0.5NbO3（KNN） in paraelectric cubic phase were calculated employing the plane-wave pseudopotential method based on density functional theory （DFT）.The calculated electronic structures of the three crystals show similar features in the valence bands and the lower conduction bands.However,the structures in higher conduction bands differ markedly due to the effect of Na and K atoms.The calculated optical properties reveal that the features of optical spectrum at low energy are dominated by the transitions from O2p valence bands to Nb 4d conduction bands and those at high energy are related to the transitions to K 4s4p and/or Na 3s3p states.Moreover,the optical constants of KNN are approximately the average of KN and NN at high energy.Therefore,the optical properties of KNN in high energy region can probably be altered by changing the ratio of Na/K.The structural,electronic and optical properties of KNbO 3 （KN）,NaNbO3（NN）and K05 Na0.5NbO3（KNN） in paraelectric cubic phase were calculated employing the plane-wave pseudopotential method based on density functional theory （DFT）.The calculated electronic structures of the three crystals show similar features in the valence bands and the lower conduction bands.However,the structures in higher conduction bands differ markedly due to the effect of Na and K atoms.The calculated optical properties reveal that the features of optical spectrum at low energy are dominated by the transitions from O2p valence bands to Nb 4d conduction bands and those at high energy are related to the transitions to K 4s4p and/or Na 3s3p states.Moreover,the optical constants of KNN are approximately the average of KN and NN at high energy.Therefore,the optical properties of KNN in high energy region can probably be altered by changing the ratio of Na/K.

关 键 词：the first principle electronic structure optical properties （K Na）NbO 3 

分 类 号：O614.112[理学—无机化学]