Negligible Sr segregation on SrTiO_3(001)-(13~(1-2)×13~(1-2))-R33.7° reconstructed surfaces

摘要

We compare the extent of Sr segregation on buffered-HF (BHF)-etched and (13~(1-2) ×13~(1-2))-R33.7° reconstructed SrTiO_3(001) surfaces, and reveal that Sr segregation is suppressed on the reconstructed surface. Scanning tunneling microscopy and photoemission studies of both surfaces show distinct differences in terms of atomic arrangements, electronic structures, and chemical states. The emission-angle-dependent Sr 3d core-level spectra indicate that the amount of Sr is low at the surface of the reconstructed surfaces, while the amount increases near the surface of the BHF-etched surface. Our investigations would facilitate the preparation of a compositionally well-defined SrTiO_3 surface that is of significant importance to accelerate oxide electronics research.