ABO3-type oxides constitute an important class of materials for applications in many areas of modern technology and are of fundamental scientific interest. Despite their chemical simplicity, these perovskite compounds are crystallographically subtle, because they exhibit a wide variety of complex structural instabilities, including ferroelectric, antiferroelectric, and antiferrodistortive distortions. The competition between these various instabilities manifests itself in different ways, depending on the chemical species involved, leading to the unusual variety and richness of microscopic structures. Among the different theoretical methods, the shell model is an effective tool for gaining fundamental insights into the underlying mechanisms behind their microscopic properties while providing a quantitative connection to ab-initio calculations and mesoscale models. Here, we will present the development of a potential for BaTiO3, as well as its extension, in order to describe the effects of Mg impurities in its composition and to analyze the possibility of a low-temperature non-cubic phase in BaZrO3. Limitations and possible future directions in the atomic-level simulations are outlined.
The seminar will be chaired by Jiří Hlinka, Department of Dielectrics.