K(Ta_(0.56)Nb_(0.44))O_3四方铁电结构的第一性原理研究  

FIRST-PRINCIPLES STUDY OF TETRAGONAL FERROELECTRIC STRUCTUER OF K(Ta_(0.56)Nb_(0.44)O_3 

作　　者：彭毅萍[1] 王渊旭[1] 张磊[1] 张沛霖[1] 钟维烈[1] 

机构地区：[1]山东大学物理系,济南250100

出　　处：《物理学报》2000年第6期1140-1143,共4页Acta Physica Sinica

基　　金：国家重点基础研究规划项目!(批准号 :G19980 6 14 0 4 0 6 )资助的课题&&

摘　　要：在广义梯度近似 (GGA)下利用全电势线性化的缀加平面波法 (FLAPW )的总能量计算 ,确定了K(Ta0 .56Nb0 .4 4)O3固溶体的四方精细结构 ,即B位离子 (Ta和Nb)在铁电相的平衡构型 .结果表明 ,Ta相对于氧八面体沿 [0 0 1]方向有约为 0 0 0 5nm的偏心位移 ,而Nb的偏心位移约为 0 0 16nm 。Based on the results of total\|energy calculations using full\|potential linearized augmented plane wave method within the generalized gradient approximation (GGA),we determined the tetragonal fine structure of K(Ta\-\{0.56\}Nb\-\{0.44\})O\-3,i.e.,the equilibrium configuration of B \|site cations (Ta and Nb)in the ferroelectric phase. Ta is found to have an off\|center displacement,relative to the oxygen octahedron,of about 0.005?nm along \\]. The off\|center displacement of Nb is as large as 0.016?nm,thus makes a major contribution to the occurrence of the ferroelectric instability. . The off\|center displacement of Nb is as large as 0.016?nm,thus makes a major contribution to the occurrence of the ferroelectric instability.

关 键 词：KTN 铁电材料 四方铁电结构 第一性原理 

分 类 号：TM22[一般工业技术—材料科学与工程]