**Acknowledgements**

The authors thank former and present team members, Wilhelm von Rosenberg, Laura Doll, Jens Rösler, Stefan Stein, Michael Stuhlmüller, Jin-Ho Lee, Florence Laure Djikimi Tchetgna, Matthias Krufczik, Aaron Sievers, and Jutta Schwarz-Finsterle at the Kirchhoff-Institute of Physics, Heidelberg University for images taken from their theses and publications.
