- Applied Quantum Systems

Main goal of the AQS group is to fabricate quantum devices on solid state basis and develop new methods to fulfil this task. Our technology of choice is ion beam implantation. Ions with kinetic energies allow the three dimensional modification of all types of solid state materials in a very controlled way. We run different types of accelerators that deliver all types of ions of the periodic table with kinetic energies between a few eV until several MeV. These systems are able to modify or analyse all types of materials from the surface to serval micrometers depth. One of our challenges is to perform a deterministic single ion implantation in order to assemble single atoms or defects with nanometer lateral resolution within all three dimensions. This topic will be realised using focused ion beams with an image charge detector and installed at the Leibniz Joint Lab in cooperation with the Leibniz Institute of Surface Engineering (IOM). In cooperation with the Stuttgart group (Prof. Wrachtrup) and Ulm group (Prof. Jelezko), we were able to fabricate the first entangled quantum system based on nitrogen–vacancies (NV) centres in diamond at room temperature. Ion implantation is also be used to build magnetic sensors with atom size lateral resolution to perform single molecule nuclear magnetic resonance (NMR). Besides the modification with ion beams, we run a different number of analytical tools like optical detection of magnetic resonance (ODMR), Hanbury, Brown and Twiss (HBT) or spectroscopic measurements to investigate the outcome. The possibility of preparation, modification and quality control of quantum devices on the same place and with state of the art systems is unique and guarantees a fast optimisation. This is the reason why our lab is in use by a large number of cooperation groups.
Besides the activities in quantum technology, we are specialised in defect engineering using ion beams as well as nuclear analytics by high lateral resolution proton induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) or Channeling. These experiments can performed routinely at a lateral resolution below 500 nm with the microbeam system LIPSION. In special cases the system is able to provide a 2 MeV proton beam with 40 nm in diameter and makes LIPSION to one of the top MeV microbeam systems worldwide.

All results show here are only possible due to our funding agencies, which we would like to express our deepest gratitude in particular the VolkswagenStiftung, the Deutsche Forschungsgemeinschaft (DFG), the European Social Fund (ESF), the European Union (EU) and the Senatsausschuss Wettbewerb (SAW) Project of the Leibniz Association.