First-principles study on intrinsic point defects properties in CaCu3Ti4O12

Defect regulation in ceramic materials is crucial for their application. This study comprehensively investigates the influence of neutral vacancy point defects in CaCu₃Ti₄O₁₂ using density functional theory calculations. The results highlight the relationship between the two primary point defects, oxygen and copper vacancies, and establish the dominant role of oxygen vacancies, which aligns well with experimental data. The formation mechanisms and interrelationships of two microstructures, the TiO₆ octahedron and the CuO₄ square, were also examined, along with their effects on the electronic structure of CaCu₃Ti₄O₁₂. This analysis reveals the fundamental relationship between crystal structure and dielectric properties. The study demonstrates the essential impact of intrinsic point defects on band structures, density of states, and dielectric properties, providing a necessary theoretical complement to experimental research and offering fundamental guidance for optimizing the dielectric performance of CaCu₃Ti₄O₁₂.