Spin-polarized Scanning Tunneling Microscopy (SP-STM)
The topic of non-collinear magnetism in ultrathin films has been our main research interest for the past years. The first discovery of a nano-scale magnetic ground state, i.e. one that is neither ferromagnetic nor antiferromagnetic, in an ultrathin film, was enabled by the combination of high spatial resolution and spin sensitivity of spin-polarized scanning tunneling microscopy. In the following years we have discovered a variety of different complex spin textures with this method and the strong collaboration between our experimental group with theory has facilitated an in-depth understanding of several mechanisms that lead to nano-scale non-collinear magnetic order.
More recently we have also studied magnet-superconductor-hybrid systems, where an ultra-thin magnetic film is grown on elemental superconductors. We have put particular emphasis on antiferromagnetic and non-collinear spin textures, and found that they give rise to topological nodal point superconductivity with chiral low-energy edge modes.
Another research area is symmetry breaking by magnetic order, which has lead to the discovery of superposition domain walls in antiferromagnets. Furthermore, such symmetry breaking facilitates the uniaxial motion of single adatoms on magnetic surfaces, and can be exploited to obtain quasi-one-dimensional growth on magnetic films on high-symmetry substrates.
