Hybrid functionals applied to rare-earth oxides: The example of ceria
Hybrid functionals applied to rare-earth oxides: The example of ceria
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DOI：
10.1103/physrevb.75.045121
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发表时间：
2007-01-01
影响因子：
3.7
通讯作者：
Kresse, Georg
中科院分区：
文献类型：
--
作者：
Da Silva, Juarez L. F.;Ganduglia-Pirovano, M. Veronica;Kresse, Georg
我们报告周期性密度泛函理论（DFT）计算CeO 2和Ce 2 O3使用Perdew-Burke-Ernzerhof（PBE 0）和Heyd-Scuseria-Ernzerhof（HSE）混合泛函，包括非局部Fock交换。我们研究结构，电子和磁基态性质。混合泛函正确地预测Ce 2 O3是一个绝缘体，而不是由局部自旋密度（LDA）和广义梯度（GGA）近似预测的铁磁金属。这两种结构的平衡体积与实验非常吻合，改进了LDA和GGA的描述。计算得到的CeO 2（O 2 p-Ce 5d）和Ce 2 O3（Ce 4f-5d 4f）的带隙比实验值分别大45%（PBE 0）和15%（HSE）。计算了2CeO（2）-> Ce 2 O3+（1/2）O-2的原子化能、生成热和还原能。后者被低估了类似的0.4-0.9 eV相对于现有的实验数据在室温下。我们比较我们的结果与更传统的DFT+U（LDA+U和PBE+U）的方法，并讨论了哈伯德U参数所发挥的作用。
We report periodic density functional theory (DFT) calculations for CeO2 and Ce2O3 using the Perdew-Burke-Ernzerhof (PBE0) and Heyd-Scuseria-Ernzerhof (HSE) hybrid functionals that include nonlocal Fock exchange. We study structural, electronic, and magnetic ground state properties. Hybrid functionals correctly predict Ce2O3 to be an insulator as opposed to the ferromagnetic metal predicted by the local spin density (LDA) and generalized gradient (GGA) approximations. The equilibrium volumes of both structures are in very good agreement with experiments, improving upon the description of the LDA and GGA. The calculated CeO2 (O 2p-Ce 5d) and Ce2O3 (Ce 4f-5d4f) band gaps are larger by up to 45% (PBE0) and 15% (HSE) than found in experiments. Furthermore, we calculate atomization energies, heats of formation, and the reduction energy of 2CeO(2)-> Ce2O3+(1/2)O-2. The latter is underestimated by similar to 0.4-0.9 eV with respect to available experimental data at room temperature. We compare our results with the more traditional DFT+U (LDA+U and PBE+U) approach and discuss the role played by the Hubbard U parameter.