The vicinal (001) surface of a Nb-doped SrTiO3 single crystal has been investigated by scanning tunneling microscopy and low energy electron diffraction. The stepped surface prepared by annealing in ultrahigh vacuum at 250 °C exhibits a complex atomic structure composed of four types of reconstructions, which shows short-range variation within nanoscale regions. SrO layers show a c (6×2) structure being stable up to 1000 °C, while √13×√13-R33.7°, c (√13×√13) -R33.7°, and c (√2×√18) -R45° structures are formed on TiO 2 layers, which disappear at 450-750 °C followed by the formation of 2×2 and √5×√5-R26.6° structures. These results indicate instability of the reconstructions on the TiO2 terminated surface due to the variation in Sr adatom density caused by multikinetic processes, in contrast to the thermodynamically stable SrO terminated surface.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)