1. Center for Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Denmark
2. Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
3. CAMECA Instruments, Inc., Madison, Wisconsin 53711, USA
4. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungzentrum Jülich, Jülich, Germany
5. Department of Physics and Astronomy, University of Bologna, Bologna, Italy