The ERC Starting Grant funded line of research focuses on the creation of a new two-dimensional (2D) building block: the 2D sandwich. This is a layered heterostructure, consisting of a mix of layered van der Waals, layered ionic and layered metavalent materials. In the 2D sandwich, an interaction between the sandwich's individual layers is mediated via an ionic or multivalent bond (gray cloud between the layers in the picture), whereas the interaction with other 2D layers is still solely due to the van der Waals interactions (yellow cloud between the layers in the picture). There are still many open, fundamental questions concerning the creation of 2D sandwiches. We explore design strategies to create such heterostructures and try to answer if and how materials with a van der Waals bond can be combined with layered ionic and layered metavalent materials. The ultimate aim of the project is to create a 2D sandwich, which will be multiferroic working at ambient conditions.
2D magnetoelectric multiferroic sandwiches composed of layered transition metal chalcogenides, oxides or iodides will be grown using the modulated elemental reactants method. Using a combination of X-ray diffraction, electron microscopy and optical spectroscopy, we will explore their structure and properties and try to answer fundamental questions if and how materials with a van der Waals bond can be combined with layered ionic and layered metavalent materials and how the interaction between them might result in multiferroicity.