Farinacci Group

We are a junior research group at the Institute for Functional Matter and Quantum Technologies, within the University of Stuttgart. We are part of the Carl-Zeiss-Stiftung Center for Quantum Photonics. In our group we use scanning tunneling microscopy combined with state-of-the-art techniques such as electron spin resonance, pump-probe and stochastic resonance spectroscopy to investigate the interplay between magnetism, superconductivity and electro-magnetic fields.

Topological states are states of matter that are very robust against local perturbations such as local fluctuations of an electric or magnetic field. This renders them very attractive for quantum computing. A promising route to design topological states is to control the interactions between a magnetic material and a superconductor.

With a scanning tunneling microscope one can precisely determine and control the position of magnetic atoms on a superconductor. Therefore, researchers have so far focused on controlling interactions in these systems by carefully tuning their spatial arrangement. We want to complement this approach by controlling the interactions over time. This requires first to understand the dynamics of these systems, which take place in the ps and ns timescales. This is challenging because measurements in STM are very slow and we only process time-averaged information. To overcome this limitation, we will use recent technological developments that allow to combine STM with other techniques (electron spin resonance, stochastic resonance and pump-probe spectroscopy) which allow us to detect change in these systems within these timescales.

Moreover, these techniques will give us fundamental insights into the interaction between magnetism, superconductivity and light. Our goal is to control the topological character of systems that we will design spatially by controlling the position of magnetic adsorbates and tune temporally by changing the frequency of the light with which they interact.

The research project is funded by the Carl-Zeiss-Stiftung Center for Quantum Photonics Jena-Stuttgart-Ulm whose goal is to bring basic research in quantum technologies and photonics to application. The Carl-Zeiss-Stiftung is one of the oldest and biggest private science funding institutions in Germany.

The thesis focuses on achieving coherent control of topological superconductivity by investigating magnetic impurities' interactions with superconductivity and electromagnetic fields. Supervised by Dr. Laëtitia Farinacci and Prof. Sebastian Loth at the University of Stuttgart, the project combines scanning tunneling microscopy and electron spin resonance to study magnetic bound states in superconductors (Yu-Shiba-Rusinov states) with neV resolution and explore their dynamics. It also involves examining quasi-particle excitations' free evolution through DC-pump-probe and stochastic resonance spectroscopy. Additionally, the project entails engineering magnetic textures with atomic precision via the self-assembly of magnetic molecules on superconductors.

If you are interested in the project and want to learn more details, feel free to contact us!

Laëtitia Farinacci:
laetitia.farinacci@fmq.uni-stuttgart.de
+49 711 685 61642

Sebastian Loth:
sebastian.loth@fmq.uni-stuttgart.de
+49 711 685 65252