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

摘要: We report periodic density functional theory (DFT) calculations for ${\mathrm{CeO}}_{2}$ and ${\mathrm{Ce}}_{2}{\mathrm{O}}_{3}$ using the Perdew-Burke-Ernzerhof (PBE0) Heyd-Scuseria-Ernzerhof (HSE) hybrid functionals that include nonlocal Fock exchange. study structural, electronic, magnetic ground state properties. Hybrid correctly predict to be an insulator as opposed ferromagnetic metal predicted by local spin (LDA) generalized gradient (GGA) approximations. The equilibrium volumes of both structures are in very good agreement with experiments, improving upon description LDA GGA. calculated (O $2p$--Ce $5d$) $(\mathrm{Ce}\phantom{\rule{0.3em}{0ex}}4f\text{\ensuremath{-}}5d4f)$ band gaps larger up 45% 15% than found experiments. Furthermore, we calculate atomization energies, heats formation, reduction energy $2{\mathrm{CeO}}_{2}\ensuremath{\rightarrow}{\mathrm{Ce}}_{2}{\mathrm{O}}_{3}+(1∕2){\mathrm{O}}_{2}$. latter is underestimated $\ensuremath{\sim}0.4--0.9\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ respect available experimental data at room temperature. compare our results more traditional DFT+$U$ (LDA$+U$ PBE$+U$) approach discuss role played Hubbard $U$ parameter.