AVS 61st International Symposium & Exhibition
    Surface Science Tuesday Sessions
       Session SS+AS+EN-TuM

Paper SS+AS+EN-TuM1
Coexisting Accessible Surface Phases on BaTiO3 (001)

Tuesday, November 11, 2014, 8:00 am, Room 309

Session: Synthesis, Structure and Characterization of Oxides
Presenter: Erie Morales, University of Pennsylvania
Authors: E.H. Morales, University of Pennsylvania
J.M. Martirez, University of Pennsylvania
W.A. Saidi, University of Pittsburgh
A.M. Rappe, University of Pennsylvania
D.A. Bonnell, University of Pennsylvania
Correspondent: Click to Email
Novel ferroelectric BaTiO3 applications ranging from sensors to nanogerators require a detailed understanding of atomic interactions at surfaces. Single crystals provides a platform that allows the explotation of surface physical and chemical properties that can be readily transferred to other ABO3 perovskite structures. The processes that result in the atomic and electronic structures of surfaces in tandem with details of surface reactivity are necessary steps towards an understanding of BaTiO3. Here we demonstrate that two surface reconstruction phases can coexist on a surface and explain the stability of the surface with a quantitative comparison of thermodynamic and kinetic considerations. Specifically, scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) of atomically resolved c(2x2) and c(4x4) reconstructions on BaTiO3 (100) are compared with density functional theory models to determine the structures of the phases. First principles calculations are also used to examine the thermodynamic stability of the phases and the reaction pathways to both the stable and meta stable structures. We also show the atomic structures of 1 D interfaces between the phases. The ferroelectric properties of BaTiO3 lead to polarization dependent surface reactions and recent results based on poling at atomic level and will be discussed.