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arXiv 1403.7650cond-mat.mtrl-scicond-mat.str-el
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由DFT计算缺氧CeO $_{2-δ}$的电子结构和激发态

Electronic structure and excitations in oxygen deficient CeO$_{2-δ}$ from DFT calculations

T. Jarlborg, B. Barbiellini, C. Lane, Yung Jui Wang, R. S. Markiewicz, Zhi Liu, Zahid Hussain, A. Bansil

摘要:

用密度泛函理论计算了CeO $_{2-δ}$超晶胞的电子结构。广义梯度近似(GGA)能很好地再现晶格常数、体积模量和磁矩等平衡性质。电子激发模拟强有力的总能量计算与原子核或价空穴的约束状态。原始的氧化铈CeO $_2$被发现是一种非磁性绝缘体,一旦从结构中去除氧,磁性就会出现。在有缺陷的氧化铈的基态中,Ce- $f$多数带位于费米能级附近,但由于终态效应,在光电子能谱实验中出现在费米能级以下约2 eV处。我们还通过计算Ce-M $_5$和O-K X射线吸收光谱中的阈值能量并将理论预测与相应的测量结果进行比较来测试我们的计算方法。我们的研究结果,$f$电子驻留在费米能级附近的缺氧氧化铈的基态是至关重要的理解CeO $_2$和相关材料的催化性能。

英文摘要:

The electronic structures of supercells of CeO$_{2-δ}$ have been calculated within the Density Functional Theory (DFT). The equilibrium properties such as lattice constants, bulk moduli and magnetic moments are well reproduced by the generalized gradient approximation (GGA). Electronic excitations are simulated by robust total energy calculations for constrained states with atomic core- or valence-holes. Pristine ceria CeO$_2$ is found to be a non-magnetic insulator with magnetism setting in as soon as oxygens are removed from the structure. In the ground state of defective ceria, the Ce-$f$ majority band resides near the Fermi level, but appears at about 2 eV below the Fermi level in photoemission spectroscopy experiments due to final state effects. We also tested our computational method by calculating threshold energies in Ce-M$_5$ and O-K x-ray absorption spectroscopy and comparing theoretical predictions with the corresponding measurements. Our result that $f$ electrons reside near the Fermi level in the ground state of oxygen deficient ceria is crucial for understanding catalytic properties of CeO$_2$ and related materials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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