Linking diffusion kinetics to defect electronic structure in metal oxides: Charge-dependent vacancy diffusion in alumina

We study the diffusion of charged vacancies in α-Al2O3 crystal using the first-principles calculation method. We predict that the migration energy for vacancy diffusion strongly depends on the charge state of the vacancy involved. Importantly, we reveal that this charge-dependent vacancy diffusion is directly related to the electron occupancy and energy level change of the defect states of the charged vacancy in alumina. Hence, our study establishes a direct link between the diffusion kinetics and electronic structure of metal oxides.