1. Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
2. Institute of Physics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Torun, Poland
3. Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastián, Spain
4. Centro de Fı́sica de Materiales, CFM-MPC CSIC-UPV/EHU, Paseo Manuel Lardizabal 5, 20018 Donostia-San Sebastián, Spain
5. Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology, College Park, Maryland 20742, United States
6. Nanoscale Device Characterization Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
7. Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany