Energetic, Optical, and Electronic Properties of Intrinsic Electron-Trapping Defects in YAlO3: A Hybrid DFT Study

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• 作者：Lixin Ning ; Weiping Cheng ; Cuicui Zhou ; Changkui Duan ; Yongfan Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 28, 2014
• 年：2014
• 卷：118
• 期：34
• 页码：19940-19947
• 全文大小：466K
• ISSN：1932-7455

文摘

The formation energies of cation antisite defects (Y_Al and Al_Y), oxygen vacancies (V_O), and nearest-neighbor defect complexes (Y_Al鈥揂l_Y and Y_Al鈥揤_O) in various charge states in the YAlO₃ crystal are calculated using density functional theory (DFT) with a modified PBE0 hybrid functional containing 32% Hartree鈥揊ock (HF) exchange. It is found that the formation of Y_Al is more energetically favorable than Al_Y under oxygen-poor condition, consistent with the fact that the latter was not observed in experiments. On the basis of calculated optical transition energies associated with the excitons trapped at Y_Al, V_O, and Y_Al鈥揤_O, the two emission bands observed under excitonic excitation at low temperature are identified. Electronic properties of Y_Al鈥揤_O complexes in the neutral and singly negative charge states are finally investigated. It shows that the extra electron added into the negative charge state is mainly localized at 4d orbitals of Y_Al with a two-component feature of its density distribution extending axially along the Y_Al鈥揤_O direction.