Vacancy-vacancy interaction in SrTiO3 bulk and surfaces

  • Ali AlZubi (Speaker)

Activity: Talk or presentationOral presentation

Description

We employ the density functional theory (DFT) to model point defects, in particular oxygen vacancies, in the perovskite SrTiO3. We use a bulk super-cell model to calculate the formation energy of single and double O-vacancies for different arrangements in the unit cell. Our results indicate a clear trend of the defects to form one-dimensional extended structures in the ground state.

We extend the study to surfaces and calculate the interaction energy of homogeneously distributed O-vacancies on SrO- and TiO2-terminated (001) surfaces. To compare to the bulk, we investigate clustering effects, in particular on the TiO2-terminated surface. For an analysis of the results, we study the role of structural relaxations and estimate the importance of electronic effects by comparison to DFT+U calculations that simulate correlation effects via a Hubbard-U parameter. Furthermore, interaction energies on the SrO-terminated surface are compared to results for O-vacancies in the SrO plane in the Ruddlesden-Popper phases, exhibiting the importance of screening effects in the bulk matrix.

We acknowledge the DFG, SFB 917 project A4, for financial support.
Period2 Apr 2014
Event titleGermany Physics Society Annual Conference: Condensed Matter Section
Event typeConference
Conference numberDresden 2014
LocationDresden, Germany, SaxonyShow on map
Degree of RecognitionInternational