Strain-Induced Defect Superstructure on the SrTiO3(110) Surface

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 (1) over bar0]-oriented stripes on the surface. The domain boundaries are decorated by defect 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 flexible platform for the designed growth of complex oxide materials.