1. Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
2. Institute for Mineralogy, Crystallography and Materials Science, Leipzig University, Scharnhorststraße 20, 04275 Leipzig, Germany
3. Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
4. Nanosystems Initiative Munich (NIM) & Center for Nanoscience, Schellingstraße 4, 80799 München, Germany