Ordered structures of defect clusters in gadolinium-doped ceria

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Nano-domains with short-range order are common in rare-earth-doped ceria.
• Understanding defect cluster formation is crucial for ceria-based materials.

Purpose of the Study:

• Investigate the ordering structure of nano-domains in gadolinium-doped ceria.
• Determine the driving forces and mechanisms behind defect cluster growth.

Main Methods:

• Atomistic simulations were employed.
• Analysis of defect cluster aggregation and segregation of dopant cations and oxygen vacancies.

Main Results:

• Defect cluster binding energy increases with size, driving growth.
• A novel stable structure, an isosceles triangle, was identified for adjacent oxygen vacancies.
• This triangle serves as a fundamental unit for forming symmetric dumbbell structures.

Conclusions:

• The identified isosceles triangle and dumbbell structures are key building blocks for larger defect clusters.
• These findings refine the understanding of nano-domain formation in rare-earth-doped ceria, challenging previous chain models.