Realization of Electron Antidoping by Modulating the Breathing Distortion in BaBiO₃

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Antidoping schemes offer novel functionalities for materials and devices.
• Existing antidoping examples are primarily limited to correlated electron systems.
• Exploring antidoping in non-correlated systems is crucial for expanding material design principles.

Purpose of the Study:

• To demonstrate barium bismuthate (BaBiO3) as a model system for antidoping.
• To investigate the mechanism of antidoping in a main group oxide.
• To confirm the effect both theoretically and experimentally.

Main Methods:

• First-principles calculations to model the electronic structure and distortions.
• Spectroscopic experiments to validate theoretical predictions.
• Systematic variation of oxygen stoichiometry to tune electron doping levels.

Main Results:

• Theoretical calculations predicted an increased band gap in BaBiO3 due to oxygen vacancies.
• Calculations indicated enhanced Bi-O breathing distortions and annihilation of specific hybridized bands near vacancies.
• Experimental results confirmed a systematic band gap increase with electron doping, reaching ~75% enhancement at BaBiO2.75.
• The antidoping effect was observed in a material lacking strong electron correlations.

Conclusions:

• Barium bismuthate (BaBiO3) serves as a model system for achieving the antidoping effect.
• Oxygen vacancies drive the antidoping phenomenon through bond disproportionation and electronic structure modifications.
• This work expands the scope of antidoping beyond correlated electron systems, offering new avenues for functional material design.