Polarization Mediated Atomic Interactions: Water and Pt on BaTiO3 (100)

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NON TECHNICAL DESCRIPTION: Transition metal oxides represent a family of materials that is enabling new devices in applications ranging from solar cells to post CMOS electronics to communications systems to chemical catalysis. Ferroelectric compounds exhibit extreme properties related to electron spin, charge and polarization that suggest innovative pathways to some of these solutions. This project uses atomic resolution tools to determine the interactions of ferroelectric surfaces with molecules and metal clusters. Specifically, interactions of water and platinum with barium titanate are quantified. This research represents the first atomic level visualization of molecular interactions in this class of materials. A high school summer academy class in nanotechnology is offered to inspire interest in careers in science based fields and a leadership program for graduate students imparts the non-technical skills required in future leaders.TECHNICAL DETAILS: Ferroelectric compounds exhibit extreme properties related to electron spin, charge and polarization that have the potential to enable next generation devices in energy, nanoelectronics, and catalysis. This project uses scanning tunneling microscopy and spectroscopy in conjunction with other characterization tools to determine the mechanisms of molecular absorption on barium titanate (100) surfaces with and without metal clusters. The effect of Ti atomic coordination on water absorption is determined by comparing reactions on a series of surface reconstructions that vary in Ti concentration. The effect of polarization on reactions of water with Pt metal clusters is examined by comparing tunneling spectra over domains with different orientations with those of the clusters. Charge carriers that effect surface reactions are generated with optical illumination and the effect on water reactivity quantified. The results are compared to theoretical calculations in order to relate the local electronic structures to chemical interactions. The results inform advances in thin film growth, surface chemical reactivity and the physics of electronic polarization. A high school summer academy class in nanotechnology is class is offered to inspire interest in careers in science based fields and a leadership program for graduate students imparts the non technical skills required in future leaders.