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.
Period | 2 Apr 2014 |
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Event title | Germany Physics Society Annual Conference: Condensed Matter Section |
Event type | Conference |
Conference number | Dresden 2014 |
Location | Dresden, Germany, SaxonyShow on map |
Degree of Recognition | International |