Ab initio study of structural and electronic properties of SrTiO_3(001)oxygen-vacancy surfaces

摘要

First-principles calculations are employed to study the surface relaxation and electronic structure of the fully relaxed SrTiO_3(001)oxygen-vacancy surfaces with both Sr and Ti terminations.In contrast to the perfect surface,the larger surface rumples and smaller interlayer distances have been found.Some in-gap Ti 3d states at about-1.13 eV below the Fermi level were observed in the Ti-terminated surface caused by oxygen vacancies.For the Sr-terminated oxygen-vacancy surface,some in-gap Ti 3d states move into the bulk midgap region to become partially occupied.These theoretical results are in agreement with the experimental data.