1. Institute for Physics, Technical University of Chemnitz, 09126 Chemnitz, Germany
2. Faculty of Applied Physics, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands
3. Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
4. MAX IV Laboratory and Lund University, 221 00 Lund, Sweden