1. Institute for Electron Microscopy and Nanoanalysis (FELMI), Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
2. Graz Centre for Electron Microscopy (ZFE), Steyrergasse 17, 8010 Graz, Austria
3. Institute for Experimental Physics, Graz University of Technology, Petergasse 16, 8010 Graz, Austria