Tight-binding calculation of surface defects in SrTiO3.

Abstract

uv photoemission experiments on ${\mathrm{SrTiO}}_{3}$(100) surfaces have shown that deep localized levels are associated with a lack of oxygen atoms on these surfaces. Using a tight-binding parametrization of the band structure of ${\mathrm{SrTiO}}_{3}$, together with a Green's-function method, we have calculated the energy levels associated with (100) surfaces, oxygen vacancies in these surfaces, and two kinds of adsorbed Ti atoms. The results of the calculation indicate that the observed deep levels are associated with the adsorbed titanium atoms rather than directly related to the oxygen vacancies.