Theoretical Study of Ferroelectric and Optical Properties in the 180° Ferroelectric Domain Wall of Tetragonal BaTiO3
Theoretical Study of Ferroelectric and Optical Properties in the 180° Ferroelectric Domain Wall of Tetragonal BaTiO3
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四方BaTiO3 180°铁电畴壁铁电和光学性质的理论研究
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
L. Eng
中科院分区：
文献类型：
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作者：
H. Chaib;T. Otto;L. Eng
用微观模型讨论了四相钛酸钡（BaTiO 3）180°铁电畴壁自发极化和折射率的微观机制。这个模型的基础上的轨道近似与偶极-偶极相互作用，由于局部场作用于所有组成离子的畴壁。研究发现，自发极化和折射率的行为都取决于畴壁的厚度，畴壁的厚度在5到20埃之间变化。此外，自发极化示出了双曲正切形状的畴壁的厚度较大，然后消失在畴壁的中心。折射率表明畴壁的行为像一个双轴晶体，导致折射率分布的高斯形状的畴壁为1.20埃。这极大地影响了通过畴壁的光传输，特别是对于平行于畴壁偏振的光。
The microscopic mechanism of spontaneous polarization and refractive indices in 180° ferroelectric domain walls of tetragonal Barium titanate (BaTiO 3 ) is discussed by using a microscopic model. This model bases on the orbital approximation in correlation with the dipole-dipole interaction due to the local field acting on all constituent ions within the domain wall. It is found that the behavior of both the spontaneous polarization and the refractive indices depends on the thickness of the domain wall which was varied between 5 and 20 A. Moreover, the spontaneous polarization shows a hyperbolic tangent shape for domain walls of a larger thickness which then vanishes at the center of the domain wall. The refractive indices suggest the domain wall to act like a biaxial crystal resulting in refractive index profiles of a Gaussian shape for domain walls of ∼20 A. This dramatically affects optical transmission through the domain wall especially for light being polarized parallel to the domain wall.