A-Site Doping to Alter Oxygen Vacancy Diffusion in SrTiO₃.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Computational Materials Science

Background:

• Strontium Titanate (SrTiO3) is a key material in various electronic applications.
• Oxygen vacancy diffusion significantly impacts SrTiO3's functional properties and reliability.
• A-site doping is explored as a method to tune SrTiO3's characteristics.

Purpose of the Study:

• To investigate the effect of A-site doping (Mn, Cr, Fe) on oxygen vacancy diffusion in SrTiO3.
• To understand the mechanisms of long-range oxygen vacancy diffusion influenced by dopants.
• To provide insights into how A-site doping modifies the electronic structure of SrTiO3.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• The nudged elastic band (NEB) method was used to determine diffusion barriers.
• Calculations focused on oxygen vacancy diffusion barriers near and far from dopant sites.

Main Results:

• A-site doping with Mn2+, Cr3+, or Fe2+ alters oxygen vacancy diffusion barriers compared to pure SrTiO3.
• Doping increases diffusion barriers for V_O•• vacancies and decreases them for V_O vacancies.
• A consistent doping trapping radius of 6 Å was observed for both vacancy types, even for similarly charged species.

Conclusions:

• A-site doping significantly influences oxygen vacancy mobility in SrTiO3.
• The observed trapping effect, even between positively charged species, offers new perspectives on defect interactions.
• These findings are crucial for designing SrTiO3-based devices with tailored properties and improved stability.