Publications in Scientific Journals:
P. Scheiber, M. Fidler, O. Dulub, M. Schmid, U. Diebold, W. Hou, U. Aschauer, A. Selloni:
"(Sub)Surface Mobility of Oxygen Vacancies at the TiO2 Anatase (101) Surface";
Physical Review Letters,
Anatase is a metastable polymorph of TiO2. In contrast to the more widely studied TiO2 rutile, O vacancies
(VO´s) are not stable at the anatase (101) surface. Low-temperature STM shows that surface VO´s, created by
electron bombardment at 105 K, start migrating to subsurface sites at temperatures 200 K. After an initial
decrease of the VO density, a temperature-dependent dynamic equilibrium is established where VO´s move to
subsurface sites and back again, as seen in time-lapse STM images. We estimate that activation energies for
subsurfacemigration lie between 0.6 and 1.2eV; in comparison, density functional theory calculations predict a
barrier of ca. 0.75 eV. The wide scatter of the experimental values might be attributed to inhomogeneously
distributed subsurface defects in the reduced sample.
Created from the Publication Database of the Vienna University of Technology.