1. Institute of Physics, University of Graz, Universitätsplatz 5, Graz 8010, Austria
2. Thales Research and Technology, 1 avenue Augustin Fresnel, Palaiseau 91767, France
3. Central European Institute of Technology, Brno University of Technology, Brno Purkynǒva 123, 612 00, Czech Republic
4. University Service Centre for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10, Wien 1040, Austria