Incipient ferroelectricity: A route towards bulk-terminated SrTiO3

I. Sokolović, M. Schmid, U. Diebold, M. Setvin

Institut für Angewandte Physik, TU Wien, 1040 Wien, Austria

Phys. Rev. Materials 3 (2019) 034407

Investigation of bulk-terminated (001) surfaces of SrTiO3, a prototypical cubic perovskite, was made possible with a novel cleaving procedure. Controlled application of strain on a SrTiO3 single crystal results in a flat cleavage with µm-size domains of SrO and TiO2. Distribution of these two terminations is dictated by ferroelectric domains induced by strain during the cleavage process. Atomically resolved scanning tunneling microscopy/atomic force microscopy measurements reveal the presence of point defects in a well-defined concentration of (14 ± 2)%; Sr vacancies form at the SrO termination and complementary Sr adatoms appear at the TiO2 termination. These intrinsic defects stabilize the surface by balancing the interplay between ferroelectricity, surface polarity, and surface charge.

Corresponding author: Martin Setvin.

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