Communication: improving the density functional theory+U description of CeO2 by including the contribution of the O 2p electrons.
Density functional theory (DFT) based approaches within the local-density approximation or generalized gradient approximation frameworks fail to predict the correct electron localization in strongly correlated systems due to the lack of cancellation of the Coulomb self-interaction. This problem might be circumvented either by using hybrid functionals or by introducing a Hubbard-like term to account for the on site interactions. This latter DFT+U approach is less expensive and therefore more practical for extensive calculations in solid-state computational simulations. By and large, the U term only affects the metal electrons, in our case the Ce 4f ones. In the present work, we report a systematic analysis of the effect of adding such a U term also to the oxygen 2p electrons. We find that using a set of U(f) = 5 eV and U(p) = 5eV effective terms leads to improved description of the lattice parameters, band gaps, and formation and reduction energies of CeO(2).
Departamento de Química Física, Facultad de Química, Universidad de Sevilla, 41012 Sevilla, Spain.
José J
JJ
Plata
Antonio M
AM
Márquez
Javier Fdez
JF
Sanz