DFG Programme: Physics of van der Waals [hetero]structures
Two-dimensional (2D) materials are crystals with a thickness of only one or very few atoms. After the discovery of graphene, the most prominent representative of this class of materials, many other 2D crystals have been identified, often with intriguing properties that have no counterparts in three-dimensional solids.
Read more about SPP 2244: 2D Materials – Physics of van der Waals [hetero]structures (2DMP)
Subproject
Since 2020
1D topological superconductivity and Majorana states in van der Waals heterostructures characterized by scanning probe microscopy
Topological superconductivity is an exotic state of matter with potential applications in quantum computing. A promising approach to realize topological superconductivity is to use a conventional superconductor to induce superconductivity in a topological edge state via the superconducting proximity effect. Using a newly developed sample fabrication technique, the ‘dry-transfer flip technique’, as well as epitaxial thin films which are grown by our collaborators, we propose to create van der Waals (vdW) heterostructures of two-dimensional, atomically thin layers of topological insulators WTe2 and (Bi(1-x)Sb(x))2Te3 on superconducting NbSe2 and FeTe(1-y)Se(y). Using scanning probe microscopy at low temperatures and in ultra-high vacuum, we then characterize the induced superconductivity in the topological edge state. By combination of a topological superconductor with some form of magnetism, e.g. a magnetic layer, a magnetic cluster or by application of an external magnetic field, so-called Majorana quasi-particles can be created in the topological superconductor. We propose to realize and study Majorana states created in the vdW heterostructures to gain a deeper understanding of the underlying physics. Another sample system in which we propose to realize Majorana states are atomically thin layers of NbSe2 which are placed on a vdW magnet such as Fe3Ge1Te2. Our experimental characterization will be supported by theoretical calculations from our collaborators within the programme.