A-Site Doping to Alter Oxygen Vacancy Diffusion in SrTiO3

Doped SrTiO3 is a promising material for many applications where oxygen vacancy diffusion is either critical to device function or a source of failure. This work provides new insight into long-range oxygen vacancy diffusion in SrTiO3 doped with Mn2+, Cr3+, or Fe2+ on the A-site. Density functional theory and the nudged elastic band method are used to calculate oxygen vacancy diffusion barriers adjacent to the dopant and at remote sites. Relative to the pure SrTiO3 structure, doping was found to raise the diffusion barrier for VO•• vacancies and lower the diffusion barrier for VOx vacancies. Furthermore, a doping trapping radius of 6 Å was found for both the VOx and VO•• vacancies. Counterintuitively, trapping was observed even in supercells where vacancies and dopants are both positively charged. These results provide new insight into how less common A-site doping can change the electronic structure of this important material.