1. Institute of Physics (IPHYS); École Polytechnique Fédérale de Lausanne (EPFL); Station 3 CH-1015 Lausanne Switzerland
2. Institute of Nanotechnology; Karlsruhe Institute of Technology (KIT); D-76344 Eggenstein-Leopoldshafen Germany
3. Institut de Physique et Chimie des Matériaux (IPCMS); Université de Strasbourg; F-67034 Strasbourg France
4. Swiss Light Source; Paul Scherrer Institut (PSI); CH-5232 Villigen Switzerland