First-principles embedded-cluster calculations of the neutral and charged oxygen vacancy at the rutile TiO${}_2$(110) surface

Abstract

We perform full-potential screened-hybrid density-functional theory (DFT) calculations to compare the thermodynamic stability of neutral and charged states of the surface oxygen vacancy at the rutile TiO${}_2$(110) surface. Solid-state (QM/MM) embedded-cluster calculations are employed to account for the strong TiO${}_2$ polarization response to the charged defect states. Similar to the situation for the bulk O vacancy, the +2 charge state $V_{\mathrm{O}}^{2+}$ is found to be energetically by far most stable. Only for Fermi-level positions very close to the conduction band, small polarons may at best be trapped by the charged vacancy. The large decrease of the $V_{\mathrm{O}}^{2+}$ formation energy with decreasing Fermi-level position indicates strongly enhanced surface O vacancy concentrations for $p$-doped samples.

References in corpus (3)

• A direct view at excess electrons in TiO${}_2$ rutile and anatase
• Quasiparticle level alignment for photocatalytic interfaces
• Embedded-Cluster Calculations in a Numeric Atomic Orbital Density-Functional Theory Framework

Cited by in corpus (4)

• Formation and dynamics of small polarons on the rutile TiO${}_2$(110) surface
• Theoretical evidence for unexpected O-rich phases at corners of MgO surfaces
• Oxygen-vacancy driven electron localization and itinerancy in rutile-based TiO${}_2$
• General embedded cluster protocol for accurate modeling of oxygen vacancies in metal-oxides