Andreev reflection spectroscopy of magnetic impurities on superconductors at the single-atom level

• Applicant: Professor Dr. Jörg Kröger
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 500665567

The Andreev reflection will be studied in single-atom and singlemolecule contacts with a scanning tunnelling microscope. By exploiting the advantages of the experimental method, namely the flexibility in choosing the electrode materials – tip and singlecrystalline surface – as well as the atomically precise characterization of the contact, the potential dependence of Andreev reflection on the phase coherence length of the superconductor will be explored. Moreover, the analysis of the spin polarization of the current on the basis of Andreev reflection in macroscopic point contacts comprising magnetic and superconducting electrodes will be transferred and established for single-atom and single-molecule contacts formed with a scanning tunnelling microscope. The use of superconducting tips and samples as well as magnetic impurities adsorbed on either the tip or the sample surface is planned to unveil the relation between Andreev reflection, Yu-Shiba-Rusinov states and the hybridization of the magnetic atoms and molecules with the electrodes.

• DFG Programme: Research Grants