Electron–electron correlations and structural, spectral and polarization properties of tetragonal BaTiO 3
Electron–electron correlations and structural, spectral and polarization properties of tetragonal BaTiO 3
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四方 BaTiO 3 的电子-电子相关性以及结构、光谱和偏振特性
DOI：
10.1088/1361-648x/abaa81
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Turkowski, Volodymyr
中科院分区：
文献类型：
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作者：
Din, Naseem Ud;Jiang, Tao;Gholam-Mirzaei, Shima;Chini, Michael;Turkowski, Volodymyr
为了分析电子-电子相关效应在正方batio3的结构（局域几何）、光谱和极化特性中的作用，我们采用了DFT+ U方法。我们证明了当局域库仑斥力U超过临界值U c≈7 eV时，系统性质会发生剧烈变化。特别是，相关效应引起了面内和面间Ti - o键长比值的变化，从而导致了Ti - o带的顺序翻转和体系极化率的变化。由于batio3中U的一致值是未知的，我们讨论了所得结果如何在实验数据中揭示，特别是在光学响应和超快电荷动力学中，其中有效U是动态调谐的。
To analyze the role of electron–electron correlation effects in structural (local-geometry), spectral and polarization properties of tetragonal BaTiO 3 we apply DFT+ U approach. We demonstrate that the system properties drastically change when the value of the local Coulomb repulsion U crosses the critical value U c≈ 7 eV. In particular, the correlation effects cause a change of the ratio of the in-plane and inter-plane Ti–O bond lengths, which results in a flip of the order of the Ti d-bands and change of the polarizability of the system. Since the consensus value of U in BaTiO 3 is unknown, we discuss how the obtained results may be revealed in experimental data, especially in the optical response and ultrafast charge dynamics, where effective U is dynamically tuned.