Session Z10: Novel Instrumentation and Techniques in Surface Science

11:15 AM–2:03 PM, Friday, March 25, 2011
Room: D221

Sponsoring Unit: DCMP
Chair: Ray Phaneuf, University of Maryland

Abstract ID: BAPS.2011.MAR.Z10.12

Abstract: Z10.00012 : Reduction of a polar oxide surface in a strong DC-field

1:27 PM–1:39 PM

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Authors:

  Wolfram Steurer
    (Institute of Physics, University of Graz, Universitaetsplatz 5, Graz, A-8010, Austria)

  Svetlozar Surnev
    (Institute of Physics, University of Graz, Universitaetsplatz 5, Graz, A-8010, Austria)

  Giovanni Barcaro
    (IPCF/CNR, via G. Moruzzi 1, Pisa, I-56124, Italy)

  Alessandro Fortunelli
    (IPCF/CNR, via G. Moruzzi 1, Pisa, I-56124, Italy)

  Falko P. Netzer
    (Institute of Physics, University of Graz, Universitaetsplatz 5, Graz, A-8010, Austria)

Polar oxide surfaces are of fundamental scientific interest because of their inherent instability in bulk samples on electrostatic grounds. Here we report first experimental evidence of field-induced reduction of a polar oxide surface by applying homogeneous external DC-fields. Ultrathin Ni-oxide nanostructures immersed into an Ag(100) substrate have been grown by reactive evaporation and have subsequently been exposed to electric fields in the range of 0.5-1.6 V/nm. We achieve such high fields in a setup resembling a plate capacitor where the Ag(100) substrate (with the deposited NiO film) acts as the cathode with a counter electrode placed 800nm apart. For fields exceeding the threshold of 0.9 V/nm, oxygen atoms are torn away from the surface, thus, efficiently reducing the initially highly-ordered Ni-oxide film. The remaining Ni atoms on the surface are highly mobile and cluster together. No oxide reduction occurs if the field polarity is inverted.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.Z10.12