1. Karlsruhe Institute of Technology (KIT), Institute for Technical Physics (ITEP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
2. University of Geneva, Department of Quantum Matter Physics (DQMP), Quai Ernest-Ansermet 24, 1211 Geneva, Switzerland
3. Karlsruhe Institute of Technology (KIT), Laboratory for Electron Microscopy (LEM), Engesserstr. 7, 76131 Karlsruhe, Germany