| AVS 54th International Symposium | |
| Surface Science | Wednesday Sessions |
| Session SS2-WeA |
| Session: | Oxide Surface Structure I |
| Presenter: | Z. Zhang, Pacific Northwest National Laboratory |
| Authors: | Z. Zhang, Pacific Northwest National Laboratory Q. Ge, Southern Illinois University S.-C. Li, University of Texas at Austin B.D. Kay, Pacific Northwest National Laboratory J.M. White, University of Texas at Austin Z. Dohnálek, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
Since oxygen atom vacancies play a central role in the behavior of oxide materials, determining their properties is widely pursued both experimentally and theoretically. Rutile TiO2(110) has became a model system for the studies of lattice oxygen defects - bridge-bonded oxygen vacancies (BBOV’s). Despite that, surprisingly little is known about the spatial distribution and/or mobility of these BBOV sites. As a function of temperature between 340 and 420 K, we report here the first measurements and calculations of the intrinsic mobility of BBOV’s on a rutile TiO2(110) surface. Under conditions where interference by adsorbates was negligible, isothermal atomically-resolved scanning tunneling microscope images that track individual vacancies in real time show that vacancies migrate along bridge-bonded oxygen (BBO) rows. The hopping rate increases exponentially with increasing temperature with experimental activation energy of 1.15 eV. Density functional theory calculations are in very good agreement giving an energy barrier for hopping of 1.03 eV. In agreement with the theory, the BBOV distribution determined by analysis of the STM images indicates short-range repulsive interactions between vacancies on a given BBO row. The research described here was performed in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.