Defect states at the TiO2(110) surface probed by resonant photoelectron diffraction

Area of Science:

• Surface Science
• Materials Science
• Quantum Chemistry

Background:

• Reduced titanium dioxide (TiO2) surfaces exhibit defect states crucial for catalytic and electronic properties.
• Understanding charge distribution in these defects is essential for tailoring material functionalities.

Purpose of the Study:

• To investigate the charge distribution of defect states on the reduced TiO2(110) surface.
• To introduce and apply resonant photoelectron diffraction as a novel method for this analysis.

Main Methods:

• Utilized resonant photoelectron diffraction, exciting defect states at the Ti-2p-3d resonance.
• Analyzed diffraction patterns using the forward scattering approach.
• Performed multiple scattering calculations for data interpretation.

Main Results:

• Determined that defect charge is distributed across multiple surface and subsurface Titanium (Ti) sites.
• Identified a specific subsurface Ti site as having the dominant contribution to the defect charge.
• Results align with theoretical predictions from density functional theory calculations.

Conclusions:

• Resonant photoelectron diffraction provides detailed insights into surface defect charge distribution.
• The charge localization on specific subsurface sites influences the properties of reduced TiO2.
• This work validates a new method for surface defect analysis.