Atomic structures of reduced SrTiO3(001) surfaces

The scanning tunneling microscope has been employed to study the reduced SrTiO₃(001) surface in ultrahigh vacuum. Topographic images show a change of structural ordering for the surface annealed under three different conditions. In addition, our STM images reveal row-like structures with spacings of 12 and 20 Å. The observations are discussed in terms of the formation of intergrowths of lamellae of Sr_{n + 1} Ti_nO_{3n + 1}; a result of accommodation of oxygen and titanium deficiencies.