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O: Fachverband Oberflächenphysik
O 27: Metal Oxide Surfaces I: Structure, Epitaxy and Growth
O 27.3: Talk
Tuesday, April 2, 2019, 11:00–11:15, H16
Atomically-resolved AFM study of the bulk-terminated SrTiO3 (001) 1x1 surface — •Igor Sokolović, Michael Schmid, Ulrike Diebold, and Martin Setvin — Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
Working with bulk-terminated perovskite surfaces is challenging since the surface preparation techniques suitable for preparation of binary oxide surfaces lead to a plethora of surface reconstructions. We successfully cleaved the prototypical cubic perovskite oxide, SrTiO3 (STO), by utilizing strain-induced ferroelectricity, and possibly found a way to cleave other cubic perovskites with no preferable planes of cleavage. The bulk-terminated (1x1) STO (001) surface was investigated by non-contact atomic force microscopy (ncAFM) which reveals that the as-cleaved surface consists of two distinct terminations: terraces with a metallic TiO2 and a semiconducting SrO termination, both being up to micrometers in size. During the cleaving Sr atoms are pulled out of the top SrO layer and remain on the opposite TiO2 surface in the form of adatoms; the concentration of these Sr adatoms is the same as the concentration of Sr vacancies on the SrO surface. These charged point defects serve as a polarity compensation mechanism for stabilizing the strain-induced polarity along the [001] direction in the crystal. Annealing the surface gradually alters the (1x1) termination and turns the surface amorphous.