1. Division of Superconductivity and Magnetism, Felix Bloch Institute for Solid State Physics, University of Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany
2. Division of Applied Quantum Systems, Felix Bloch Institute for Solid State Physics, University of Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany
3. Leibniz Institute of Surface Engineering (IOM), Permoserstrasse15, D-04318 Leipzig, Germany