The first measurements and calculations of the intrinsic mobility of bridge-bonded oxygen vacancies on a rutile TiO2(110) were reported. The sequences of isothermal (340 to 420K) scanning tunnelling microscopic images showed that bridge-bonded oxygen vacancies migrated along bridge-bonded oxygen rows. The hopping rate increased exponentially with increasing temperature with an experimental activation energy of 1.15eV. Density functional theory calculations were in very good agreement, giving an energy barrier for hopping of 1.03eV. Both theory and experiment indicate repulsive interactions between vacancies on a given bridge-bonded oxygen row.

Imaging Intrinsic Diffusion of Bridge-Bonded Oxygen Vacancies on TiO2(110). Zhang, Z., Ge, Q., Li, S.C., Kay, B.D., White, J.M., Dohnálek, Z.: Physical Review Letters, 2007, 99[12], 126105