Decoupling many-body interactions in the CeO₂(111) oxygen vacancy structure with statistical learning and cluster...

Area of Science:

• Materials Science
• Computational Chemistry
• Surface Science

Background:

• Oxygen vacancies (V_O's) significantly impact ceria (CeO₂) properties and applications.
• Understanding V_O distribution is challenging due to complex electronic configurations and many-body interactions.

Purpose of the Study:

• To develop a theoretical framework for analyzing V_O distribution and interactions in ceria.
• To identify key factors governing the stability of oxygen vacancy structures.

Main Methods:

• Utilized a cluster expansion model combined with first-principles calculations and statistical learning.
• Employed Metropolis Monte Carlo simulations for extensive sampling of V_O's and Ce³⁺ ions on CeO₂(111) surfaces.

Main Results:

• Decoupled interactions between Ce³⁺ ions and V_O's, identifying favorable attractions and repulsions.
• Discovered that oxygen vacancies aggregate and are abundant in the third oxygen layer due to geometric relaxation.
• Explored over 10⁸ configurations in an 8x8 supercell.

Conclusions:

• The study provides a novel method to understand complex vacancy structures in metal oxides.
• Findings highlight the importance of geometric relaxation in V_O aggregation.
• The research has potential implications for redox and catalytic applications of ceria.