Density-Functional Calculations of the Structure of Near-Surface Oxygen Vacancies and Electron Localization on CeO2(111)
Density-Functional Calculations of the Structure of Near-Surface Oxygen Vacancies and Electron Localization on CeO2(111)
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DOI：
10.1103/physrevlett.102.026101
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发表时间：
2009-01-16
影响因子：
8.6
通讯作者：
Sauer, Joachim
中科院分区：
文献类型：
--
作者：
Ganduglia-Pirovano, M. Veronica;Da Silva, Juarez L. F.;Sauer, Joachim
围绕CeO2（111）上氧空位最热门的问题之一是表面和次表面缺陷的相对稳定性。利用HSE06 （Heyd-Scuseria-Ernzerhof）混合泛函以及DFT+U方法（其中U是描述现场库仑相互作用的hubard类术语），我们发现具有（2x2）周期性的亚表面空位在能量上更有利0.45 (HSE06), 0.47 [PBE+U （Perdew-Burke-Ernzerhof泛函）]和0.22 eV [LDA+U（局部密度近似）]。多余的电子不是像前面所说的那样定位在离缺陷最近的Ce离子上，而是定位在次近邻的Ce离子上。用缺陷引起的晶格弛豫效应解释了多余电子分布和亚表面空位的偏好。
One of the most topical issues surrounding oxygen vacancies on CeO2(111) is the relative stability of surface and subsurface defects. Using density-functional theory (DFT) with the HSE06 (Heyd-Scuseria-Ernzerhof) hybrid functional as well as the DFT+U approach (where U is a Hubbard-like term describing the on-site Coulomb interactions), we find subsurface vacancies with (2x2) periodicity to be energetically more favorable by 0.45 (HSE06), 0.47 [PBE+U (Perdew-Burke-Ernzerhof functional)], and 0.22 eV [LDA+U (local density approximation)]. The excess electrons localize not on Ce ions which are the nearest neighbor to the defect as priorly suggested, but instead on those that are next-nearest neighbors. The excess-electron distribution and the preference for subsurface vacancies are explained in terms of defect-induced lattice relaxation effects.