  We report on a combined scanning tunneling microscopy and density functional
theory calculation study of the SrTiO3(110)-(4 x 1) surface. It is found that
antiphase domains are formed along the [1-10]-oriented stripes on the surface.
The domain boundaries are decorated by defects pairs consisting of Ti2O3
vacancies and Sr adatoms, which relieve the residual stress. The formation
energy of, and interactions between, vacancies result in a defect
superstructure. It is suggested that the density and distributions of defects
can be tuned by strain engineering, providing a fexible platform for the
designed growth of complex oxide materials.
