Atomic structure, electronic structure, and defect energetics in [001](310) Σ5 grain boundaries of SrTiO3 and BaTiO3
Atomic structure, electronic structure, and defect energetics in [001](310) Σ5 grain boundaries of SrTiO3 and BaTiO3
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DOI：
10.1103/physrevb.78.245320
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发表时间：
2008-12-01
影响因子：
3.7
通讯作者：
Ikuhara, Y.
中科院分区：
文献类型：
--
作者：
Imaeda, M.;Mizoguchi, T.;Ikuhara, Y.
为了找到原子结构、电子结构和缺陷能量之间的关系，[001](310)SrTiO3和BaTiO3的Sigma 5晶界(GB)通过使用第一性原理计算和高分辨率扫描透射电子显微镜进行了研究。研究发现，一种晶粒相对于另一种晶粒的刚体平移对于获得稳定的晶界结构是必不可少的，并且刚体平移对于减少悬空键和应变等结构畸变起着重要作用。清楚地表明，除非在显微镜图像中可以看到 O 柱，否则计算结构与显微镜图像的拟合不足以确定 GB 结构。尽管空位形成能取决于原子位点，但发现晶界处的缺陷能量与本体中的缺陷能量相似。研究还发现，Ti 空位比 Sr(Ba) 和 O 空位对结构畸变更敏感。这是由于 Ti-O 和 Sr(Ba)-O 的键合特性不同造成的。通过这项研究，确定了SrTiO3和BaTiO3的[001](310)Sigma 5 GBs的原子结构，并确定了这些GBs的特征电子结构和缺陷能量。
In order to find relationships among the atomic structure, electronic structure, and defect energetics, [001](310)Sigma 5 grain boundaries (GBs) of SrTiO3 and BaTiO3 were investigated by using first-principles calculations and high-resolution scanning transmission electron microscopy. It was found that the rigid-body translations of one grain with respect to the other are indispensable to obtain the stable GB structure, and the rigid-body translation plays an important role to reduce the structural distortions such as dangling bonds and strains. It was clearly demonstrated that a fit of calculated structures with microscopy images is not enough to determine the GB structure unless O columns can be seen in the microscopy image. Although the vacancy formation energy depends on the atomic site, the defect energetics at the GB was found to be similar to that in the bulk. It was also found that Ti vacancy is more sensitive to the structural distortions than Sr(Ba) and O vacancies. This would be caused by the difference in the bonding character of Ti-O and Sr(Ba)-O. Through this study, the atomic structures of the [001](310)Sigma 5 GBs of SrTiO3 and BaTiO3 were determined, and the characteristic electronic structures and defect energetics of those GBs were identified.