Diffusion and coalescence of vacancies and interstitials in graphite: A first-principles study

The study of dynamics of point defects in graphite is crucial for understanding the evolution of defect-induced ferromagnetism in 12C+ irradiated graphite. In this work, we perform first-principles calculations to explore the diffusion and coalescence of vacancies and interstitials in graphite. Different kinds of point defects, such as monovacancy, divacancy, ‘bridge’ and ‘spiro’ interstitials are considered using non-interacting and interacting models. The energetics, the diffusion paths, and the migration energies of these defects and the energy barriers for the reaction between these defects are predicted. The annealing behaviors of point defects and related ferromagnetism found in 12C+ irradiated graphite are discussed.