| AVS 54th International Symposium | |
| Surface Science | Wednesday Sessions |
| Session SS2-WeA |
| Session: | Oxide Surface Structure I |
| Presenter: | D.A. Bonnell, University of Pennsylvania |
| Authors: | D.B. Li, University of Pennsylvania J. Garra, University of Pennsylvania A. Kolpak, University of Pennsylvania A. Rappe, University of Pennsylvania D.A. Bonnell, University of Pennsylvania |
| Correspondent: | Click to Email |
Domain specific chemical reactivity has been demonstrated for ferroelectric surfaces in ambient and aqueous environments. To understand the factors that affect polarization dependent adsorption on ferroelectric surfaces, in situ studies in UHV were carried out on BaTiO3 and lead zirconate titanate (PZT) surfaces. Polarization was oriented in situ with a metal coated scanning probe microscope (SPM) tip, surfaces were exposed to CO2 at various dosages, and adsorption was monitored through its effect on local surface potential. Using SPM, we poled the ferroelectric substrates such that sub-micron meter sized out-of-plane domains terminate the surfaces. Surface potentials of these positive and negative domains were then measured by frequency modulation scanning surface potential microscopy (FM-SSPM). The influence of domain polarization on molecular adsorption was examined by comparing surface potential variation as a function of CO2 dosages. Positive and negative domains exhibited quantitatively different variations in surface potential. The differences are discussed in terms of possible adsorption mechanisms. The effect of the magnitude of the polarization is examined by comparing results on PZT and BaTiO3 with first principles calculations of surface relaxations and associated adsorption energies. The effect of defects is examined by comparing results on BaTiO3 single crystals before and after UHV annealing to produce oxygen vacancies.