1. Institute of NanotechnologyKarlsruhe Institute of Technology (KIT) 76128 Karlsruhe Germany
2. Institute of Theoretical Solid State PhysicsKarlsruhe Institute of Technology (KIT) 76128 Karlsruhe Germany
3. Institute for Applied MaterialsKarlsruhe Institute of Technology (KIT) 76128 Karlsruhe Germany
4. Fraunhofer IWM Wöhlerstr. 11 79108 Freiburg Germany
5. Institute of Applied PhysicsKarlsruhe Institute of Technology (KIT) 76128 Karlsruhe Germany
6. Institut FEMTO‐STUMR 6174CNRSUniversité de Bourgogne Franche‐Comté 25000 Besançon France