Oxygen-vacancy defects on the SrTiO³(001) surface: a quantum-chemical study

Abstract

A quantum-chemical study of the technologically important SrTiO₃(001) non-polar surface and of O-vacancy defects therein is reported in the present work. The computations are made using a method developed for periodic systems (crystals), which is based on the Hartree-Fock theory. The atomie rearrangement due to the surface creation is obtained for pure SrTiO₃ by means of the periodic large-unit-cell model and uses an automated geometry optimization procedure. The same technique is employed to study the electronic, structural and optical properties of the material due to the presence of the O vacancy and F centre (two electrons in an O vacancy). The computations are carried out for both cubic and tetragonal lattices. The results obtained are discussed in terms of the available experimental data.