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)-(4×1) surface. It is found that antiphase domains are formed along the [11¯0]-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.