Chiara Ricca¹, Elizabeth Skoropata², Marta D. Rossell³, Rolf Erni³, Urs Staub², Ulrich Aschauer^4,5*

1 Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland

2 Swiss Light Source, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland

3 Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland

4 Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland

5 Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Str. 2A, A-5020 Salzburg, Austria

* Corresponding authors emails: ulrich.aschauer@plus.ac.at

DOI10.24435/materialscloud:ae-cq [version v1]

Publication date: Jul 25, 2023

How to cite this record

Chiara Ricca, Elizabeth Skoropata, Marta D. Rossell, Rolf Erni, Urs Staub, Ulrich Aschauer, Combined theoretical and experimental study of the Moiré dislocation network at the SrTiO₃-(La,Sr)(Al,Ta)O₃ interface, Materials Cloud Archive 2023.114 (2023), https://doi.org/10.24435/materialscloud:ae-cq

Description

Recently a highly ordered Moiré dislocation lattice was identified at the interface between a SrTiO₃ (STO) thin film and the (LaAlO₃)₀.₃(Sr₂TaAlO₆)₀.₇ (LSAT) substrate. A fundamental understanding of the local ionic and electronic structure around the dislocation cores is crucial to further engineer the properties of these complex multifunctional heterostructures. Here we combine experimental characterization via analytical scanning transmission electron microscopy with results of molecular dynamics and density functional theory calculations to gain insights into the structure and defect chemistry of these dislocation arrays. Our results show that these dislocations lead to undercoordinated Ta/Al cations at the dislocation core, where oxygen vacancies can easily be formed, further facilitated by the presence of cation vacancies. The reduced Ti³⁺ observed experimentally at the dislocations by electron energy-loss spectroscopy are a consequence of both the structure of the dislocation itself, as well as of the electron-doping due to oxygen vacancy formation. Finally, the experimentally observed Ti diffusion into LSAT around the dislocation core occurs only together with cation-vacancy formation in LSAT or Ta diffusion into STO.

Materials Cloud sections using this data

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dislocation.tar.gz MD5md5:2344ef7cedcbcaa5d31de18989a79315	1.1 GiB	Data archive

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External references

Keywords

MARVEL/DD5 Complex oxide interface Dislocation Point defects