Band Structure Engineering Lab

We are promoting the concept of designing and optimizing future spintronic device functionalities through the design and engineering of the interfacial band structure. We are pursuing a research program focused primarily on novel topological phases and phenomena in atomically thin magnetic layers and heterostructures. We use advanced synthesis techniques and electronic band structure imaging to establish the details of band hybridizations in prospective systems, which subsequently are characterized by magnetotransport measurements. We envision that these systems will enable dissipationless edge transport and high efficiency of the charge-spin conversion in future spintronic devices. In a long-term perspective this research program can potentially contribute to progress in bio-inspired (neuromorphic) and quantum computing.

High resolution angle-resolved photoemission spectroscopy with the added spin-sensitivity (spin-ARPES) is the technique of choice to probe the electronic structure of crystalline solids. Driven by the interest in understanding the magnetic properties of surface electrons, we map band dispersions and Fermi surfaces of epitaxial thin films and novel materials such as topological insulators.

We operate two spin-ARPES setups. One of them operates at the soft x-ray undulator synchrotron radiation beamline in DELTA/Dortmund where also time-resolved experiments in the femtosecond regime will be possible in the near future. The other, lab-based system, combines high intensity He, Xe, or Kr discharge sources with cryogenic cooling to provide overall energy resolution below 6 meV.

We also use hard x-ray ARPES (HARPES) in order to obtain insight into the electronic structure of bulk and buried interfaces.

Our photoemission experiments are performed in the lab in Jülich and at various synchrotron beamlines around the globe, such as Spring8 (Japan), BESSY (Berlin), or DESY (Hamburg), Diamond (UK), Elettra (Italy).

We are also performing magnetotransport measurements on epitaxial ferromagnet/heavy metal interfaces with the goal to understand the impact of the interfacial electronic structure on spin-orbit torque physics.