The first measurements and calculations of the intrinsic mobility of bridge-bonded O vacancies on rutile (110) were reported. Sequences of isothermal (340 to 420K) scanning tunnelling microscope images showed that bridge-bonded O vacancies migrated along bridge-bonded O 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 indicated repulsive interactions between vacancies on a given bridge-bonded O row.

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