1. Max Planck Institute for Solid State Research, Heisenbergstraße 1, DE-70569 Stuttgart, Germany
2. Chair of Physical Chemistry, Montanuniversitaet Leoben, Franz-Josef-Straße 18, AT-8700 Leoben, Austria
3. Institute of Electron Microscopy and Nanoanalysis (FELMI), Graz University of Technology & Graz Centre for Electron Microscopy (ZFE), Steyrergasse 17, AT-8010 Graz, Austria