Toward an efficient f-in-core/f-in-valence switchable description for DFTB calculations of Ce 4f states in ceria

A computational protocol is developed for efficient studies of partially reduced redox-active oxides using the self-consistent charge density functional tight-binding method. The protocol is demonstrated for ceria, which is a prototypical reducible oxide material. The underlying idea is to achieve a consistent (and harmonized) set of Slater-Koster (SK) tables with connected repulsive potentials that enable switching on and off the in-valence description of the Ce 4f states without serious loss of accuracy in structure and energetics. The implicit treatment of the Ce 4f states, with the use of f-in-core SK-tables, is found to lead to a significant decrease in computational time. More importantly, it allows for explicit control of the oxidation states of individual Ce atoms. This makes it possible to freeze the electronic configuration, thereby allowing the exploration of the energetics for various meta-stable configurations. We anticipate that the outlined strategy can help to shed light on the interplay between the size, shape, and redox activity for nanoceria and other related materials.

Automated summary

A computational protocol is developed using the self-consistent charge density functional tight-binding method to study partially reduced redox-active oxides. The protocol allows for explicit control of the oxidation states of individual Ce atoms and exploration of various meta-stable configurations. This strategy can provide insights into the interplay between size, shape, and redox activity for nanoceria and related materials.