AVS 54th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP34
Surface Structure of BaTiO3 (001)

Tuesday, October 16, 2007, 6:00 pm, Room 4C

Session: Surface Science Poster Session
Presenter: D.B. Li, University of Pennsylvania
Authors: D.B. Li, University of Pennsylvania
R. Shao, University of Pennsylvania
A. Kolpak, University of Pennsylvania
A. Rappe, University of Pennsylvania
D.A. Bonnell, University of Pennsylvania
Correspondent: Click to Email

Although oxide surfaces have been extensively studied over the last 2 decades, the atomic structure of BaTiO3 (001) has received relatively little attention as a consequence of a variety of experimental challenges. The fundamental aspects of reactions on ferroelectric surfaces are critical to a range of device applications and BaTiO3 (001) is the prototypical model surface. On overcoming these challenges we have used STM, nc-AFM, LEED and AES, to show that this surface adopts a family of reconstructions depending on thermo-chemical history. Most of these structures have not been observed previously. Some of the reconstructions are reminiscent of those that occur on SrTiO3 (001) but the details differ significantly. Using a combination of density functional theory and ab initio thermodynamics, we compute the surface phase diagrams with oxygen potential as a dependent variable, since this is a critical variable in the experiment. The stabilities of reconstructions with Ba-adatoms, O-vacancies and Ti-O clusters are compared for different thermo-chemical conditions. Comparisons of the results of the calculations with the STM and nc-AFM results are used to construct atomic models for the reconstructed surfaces.