AVS 46th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS-WeP

Paper SS-WeP25
Metastable Surface Structure of KTaO@sub 3@(001) by Helium Atom Scattering@footnote 1@

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: T.W. Trelenberg, Florida State University
Authors: J.A. Li, Florida State University
T.W. Trelenberg, Florida State University
E.A. Akhadov, Florida State University
J.G. Skofronick, Florida State University
S.A. Safron, Florida State University
L.A. Boatner, Oak Ridge National Laboratory
Correspondent: Click to Email
Helium atom scattering is used for measurements of the surface structure of KTaO@sub 3@ immediately after cleaving in situ in a UHV scattering chamber. Angular distributions (ADs) of this simple perovskite insulator are measured under destructive interference conditions for steps of one-half the unit cell of KTaO@sub 3@(2Å). Initially the specular peak is very small and is flanked on each side by a satellite peak at ±0.043Å@super -1@. Over a period of one to three hours, depending upon the surface temperature, the specular peak grows in intensity while the satellite peaks decrease in intensity until they essentially disappear. The result is what appears to be a typical AD. A model consisting of uniform-width step-up and step-down terraces is presented which agrees with the initial observations. With increasing time, the terrace widths become more nonuniform and the step heights increase to the lattice spacing of the full unit cell(4Å) due to the mass transport. The first of these developments leads to a reduction of the satellite peak intensities and the second leads to an enhanced specular signal because of the constructive interference. @FootnoteText@ @footnote 1@Supported by U. S. Department of Energy grant number DE-FG02-97ER45635.