1. Physics/Department
of Natural Sciences, Åbo Akademi, Turku FI-20500, Finland
2. Department
of Applied Physics, Aalto University School of Science, P.O. Box 11100, Aalto 00076, Finland
3. Faculty
of Physics, University of Vienna, Boltzmanngasse 5, Wien 1190, Austria
4. STU Center for Nanodiagnostics, Vazovova 5, Bratislava 81243, Slovakia
5. Electron
Microscopy Group of Materials Science, University of Ulm, Ulm 89081, Germany
6. Max Planck Institute for Solid State Research, Stuttgart 70569, Germany
7. Institute
of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany