First Principles Study on Intrinsic Vacancies in Cubic and Orthorhombic CaTiO3
First Principles Study on Intrinsic Vacancies in Cubic and Orthorhombic CaTiO3
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DOI：
10.2320/matertrans.mc200813
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发表时间：
2009-05
影响因子：
1.2
通讯作者：
Hak-Sung Lee;T. Mizoguchi;Takahisa Yamamoto;Y. Ikuhara
中科院分区：
文献类型：
--
作者：
Hak-Sung Lee;T. Mizoguchi;Takahisa Yamamoto;Y. Ikuhara
采用第一原理投影增强波方法研究了立方晶系和斜方晶系CaTiO 3 中的结构弛豫和本征缺陷的形成能。研究发现，两相中的阳离子和氧空位分别在价带最大值和导带最小值附近引起额外的能级，并且正交晶系CaTiO 3 中的Ti空位引起的能级比立方CaTiO 3 更接近价带最大值。在中性孤立空位、部分肖特基和全肖特基等中性缺陷种类中，发现V Ca 2― + V O 2+ 和V O 0 分别是还原和氧化条件下正交晶系CaTiO 3 最优选的缺陷种类，而V Ca 2― + V O 2+ 部分肖特基在立方CaTiO 3 的任何气氛中始终稳定。与立方CaTiO 3 相比，发现斜方CaTiO 3 显示出更高的缺陷形成能。
The structural relaxations and the formation energies of intrinsic defects in cubic and orthorhombic CaTiO 3 were investigated by a first principles projector-augmented wave method. It was found that cations and oxygen vacancies in both phases cause extra levels near the valence band maximum and the conduction band minimum, respectively, and the Ti-vacancy induced level in orthorhombic CaTi0 3 is closer to the valence band maximum than that in cubic CaTiO 3 . Among the neutral defect species, including neutral isolated vacancy, partial Schottky, and full Schottky, it was found that the V Ca 2― + V O 2+ and V O 0 are the most preferable defect species for orthorhombic CaTiO 3 under reduction and oxidization conditions, respectively, whereas the V Ca 2― + V O 2+ partial Schottky is always stable in any atmosphere in cubic CaTi0 3 . As compared to cubic CaTi0 3 , it was found that orthorhombic CaTi0 3 shows higher defect formation energies.