Stabilization of small polarons in BaTiO3 by local distortions
Stabilization of small polarons in BaTiO3 by local distortions
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DOI：
10.1103/physrevmaterials.3.114602
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发表时间：
2019-11
影响因子：
3.4
通讯作者：
N. Tsunoda;Y. Kumagai;F. Oba
中科院分区：
文献类型：
--
作者：
N. Tsunoda;Y. Kumagai;F. Oba
用混合泛函方法研究了中的小极化子和点缺陷.基于实验证实的有序-无序相变，立方模型中包含了Ti沿方向的位移。我们发现，自陷电子在钛网站是稳定的菱形和菱形和钛偏心，这引入了反键杂化之间的最低lyingandorbitals在导带最低，是必不可少的稳定的自陷电子。我们的计算与以前的理论研究相反，即使是定性的，但合理地与长期实验观察到的小极化子一致。这一发现可以解释为什么自陷电子在中不稳定，但从对称性的角度来看是在中。
Small polarons and point defects inare investigated using hybrid functional calculations. Based on the experimentally-confirmed order-disorder-type phase transitions, Ti displacements alongdirections are included in the cubic model. We reveal that the self-trapped electrons at Ti sites are stable in both rhombohedral and cubicand the Ti off-centering, which introduces antibonding hybridization between lowest-lyingandorbitals at the conduction band minimum, is essential for stabilizing the self-trapped electrons. Our calculations are in contrast to previous theoretical studies, even qualitatively, but reasonably consistent with the long-standing experimentally-observed small polarons in. This finding may explain why self-trapped electrons are not stable inbut are infrom the symmetry viewpoint.