Charge Localization Dynamics induced by Oxygen Vacancies on the Titania TiO$_2$(110) Surface

TL;DR

This study uses ab initio molecular dynamics to explore how oxygen vacancies influence electron localization dynamics on the TiO2(110) surface, revealing complex, fluctuating behaviors that clarify previous conflicting interpretations.

Contribution

It provides the first detailed time-dependent analysis of electron localization near oxygen vacancies on TiO2(110) using ab initio simulations.

Findings

Electrons prefer the second subsurface layer but also visit surface and third subsurface layers.

Electron localization exhibits complex, fluctuating behavior over time.

Results reconcile previous conflicting experimental and theoretical interpretations.

Abstract

The dynamics of an F--center created by an oxygen vacancy on the $\mathrm{TiO_{2}(110)}$ rutile surface has been investigated using {\it ab initio} molecular dynamics. These simulations uncover a truly complex, time-dependent behavior of fluctuating electron localization topologies in the vicinity of the oxygen vacancy. Although the two excess electrons are found to populate preferentially the second subsurface layer, they occasionally visit surface sites and also the third subsurface layer. This dynamical behavior of the excess charge explains hitherto conflicting interpretations of both theoretical findings and experimental data.