Epitaxial growth and characterization of oxide and topological insulator thin films
The focus of our research are materials in thin film form, especially transition metal and rare-earth oxides which show metal-insulator transitions and interesting magnetic properties, as well as topological insulator compounds, materials having a full insulating gap in the bulk but a topologically protected conducting surface. The properties of these fascinating materials are governed by the interplay of complex interactions. Thin films and heterostructures offer a broad platform to tune these interactions, e.g. by strain, domain size, screening, proximity effects, and doping. This can provide important insights into the fundamental mechanisms that determine the properties of a material, and enables us to manipulate the characteristics of a material, for instance by inducing or suppressing phase transitions.
Our state-of-art in-house ultra-high vacuum system allows for the growth and in-situ characterization of high-quality thin films. It includes two molecular beam epitaxy chambers: one for oxides and one for topological insulators. The films are investigated all under ultra-high vacuum conditions by structural characterization using electron diffraction techniques (RHEED, LEED), investigation of the electronic structure of the bulk and surface by photoelectron spectroscopy (XPS, ARPES), and temperature-dependent resistivity measurements.