108 research outputs found
Atomically Resolved Surface Structure of SrTiO3(001) Thin Films Grown in Step-Flow Mode by Pulsed Laser Deposition
The surface structure of SrTiO3(001) thin films homoepitaxially grown by PLD
in step-flow mode was characterized using low temperature STM. It was found
that one-dimensional (1D) TiOx-based nanostructures were formed on the thin
film surface and their density increased with increasing thin film thickness.
Most of the 1D nanostructures disappeared after a post-deposition annealing,
indicating that this structure is metastable due to the nonequilibrium growth
mode. The resulting surface after annealing exhibited similar features to that
of a thinner film, having a domain structure with (2x1) and (1x2)
reconstructions, but with fewer oxygen-vacancy-type defects. These results
imply that the step-flow growth is likely to produce TiOx-rich surface and Ti
deficiencies in the film. By the post-deposition annealing, the rich TiOx would
diffuse from the surface into the film to compensate defects associated with Ti
vacancies and oxygen vacancies, resulting in the stable surface structure with
fewer oxygen vacancies. Thus, STM measurements can provide us with a
microscopic picture of surface stoichiometry of thin films originating in the
dynamics of the growth process, and can present a new approach for designing
functional oxide films.Comment: 12 pages, 4 figure
Oxygen adatoms at SrTiO3(001): A density-functional theory study
We present a density-functional theory study addressing the energetics and
electronic structure properties of isolated oxygen adatoms at the SrTiO3(001)
surface. Together with a surface lattice oxygen atom, the adsorbate is found to
form a peroxide-type molecular species. This gives rise to a non-trivial
topology of the potential energy surface for lateral adatom motion, with the
most stable adsorption site not corresponding to the one expected from a
continuation of the perovskite lattice. With computed modest diffusion barriers
below 1 eV, it is rather the overall too weak binding at both regular
SrTiO3(001) terminations that could be a critical factor for oxide film growth
applications.Comment: 7 pages including 5 figures; related publications can be found at
http://www.fhi-berlin.mpg.de/th/th.htm
Experimental demonstrations of spontaneous, solar-driven photoelectrochemical water splitting
A note on the possibility of observing De Haas-Van Alphen oscillations in magnetostriction
Topographic and electronic structure of SrTiO3(100) surface observed by scanning tunneling microscope
Mott criterion for metal–insulator transition in doped semiconductors in intense magnetic fields
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