Interplay of ferroelectricity and metal-insulator transition

For device applications, materials are often grown as thin films or with an interface to other materials. Understanding the properties in thin films and at the interface in heterostructures is therefore crucial for developing novel devices. However, they are also of great interest from a physical point of view: Growing perovskite oxides in thin films or heterostructures further increases their wide range of characteristics and allows for novel ways to control their properties.

In this project, we aim to explore the intricate interface between a rare-earth nickelate and the ferroelectric BaTiO₃. The nickelates exhibit a metal-insulator transition and possess a layer polarization, while BaTiO₃ displays a spontaneous switchable polarization without having any layer charges. By combining these two materials, we aim to explore the electrostatic changes at the interface and their impact on both materials. Charges at the interface are influenced by switching or suppression of the spontaneous polarization in the ferroelectric, the selection of the nickelate layer at the interface and the screening from the nickelate layer. Our objective is to investigate the physics at the interface and potentially gain new ways to control the properties of the two materials.