Hybrid functionals applied to rare-earth oxides: The example of ceria

Autor(en)

Juarez L. F. Da Silva, M. Verónica Ganduglia-Pirovano, Joachim Sauer, Veronika Bayer, Georg Kresse

Abstrakt

We report periodic density functional theory (DFT) calculations for CeO2 and Ce2 O3 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 Ce2 O3 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 Ce2 O3 (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 2 CeO2 ? Ce2 O3 +(1/2) O2. The latter is underestimated by ~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. Π2007 The American Physical Society.

Organisation(en)

Computergestützte Materialphysik

Externe Organisation(en)

Humboldt-Universität zu Berlin

Journal

Physical Review B

Band

75

Anzahl der Seiten

10

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.75.045121

Publikationsdatum

2007

Peer-reviewed

Ja

ÖFOS 2012

103015 Kondensierte Materie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/7ea4f750-3efe-4cda-92bb-b4627c002cba