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首页> 外文期刊>The Journal of Chemical Physics >DFT+U study of defects in bulk rutile TiO_2
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DFT+U study of defects in bulk rutile TiO_2

机译：DFT + U研究块状金红石型TiO_2中的缺陷

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摘要

We present a systematic study of electronic gap states in defected titania using our implementation of the Hubbard- U approximation in the grid-based projector-augmented wave density functional theory code, GPAW. The defects considered are Ti interstitials, O vacancies, and H dopants in the rutile phase of bulk titanium dioxide. We find that by applying a sufficiently large value for the Hubbard- U parameter of the Ti 3d states, the excess electrons localize spatially at the Ti sites and appear as states in the band gap. At U=2.5 eV, the position in energy of these gap states are in fair agreement with the experimental observations. In calculations with several excess electrons and U=2.5 eV, all of these end up in gap states that are spatially localized around specific Ti atoms, thus effectively creating one Ti3+ ion per excess electron. An important result of this investigation is that regardless of which structural defect is the origin of the gap states, at U=2.5 eV, these states are found to have their mean energies within a few hundredths of an eV from 0.94 eV below the conduction band minimum.
机译：我们使用在基于网格的投影仪增强波密度泛函理论代码GPAW中的Hubbard-U逼近实现，对缺陷二氧化钛中的电子间隙态进行了系统的研究。考虑的缺陷是块状二氧化钛金红石相中的Ti间隙，O空位和H掺杂剂。我们发现，通过对Ti 3d态的Hubbard-U参数应用足够大的值，多余的电子在空间上位于Ti位置，并以能带隙的形式出现。在U = 2.5 eV时，这些能隙态的能量位置与实验观察值完全吻合。在几个过量电子和U = 2.5 eV的计算中，所有这些最终都以能隙状态存在，这些状态在空间上位于特定的Ti原子周围，从而有效地为每个过量电子产生一个Ti3 +离子。这项研究的重要结果是，无论间隙状态的起源是什么结构缺陷，在U = 2.5 eV时，这些状态的平均能量都在导带以下0.94 eV的百分之几eV内。最低。

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