1. Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University 1 , Linköping SE-581 83, Sweden
2. Nanostructured Materials Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University 2 , Linköping SE-581 83, Sweden
3. Frederick Seitz Materials Research Laboratory and Department of Materials Science, University of Illinois 3 , Urbana, Illinois 61801, USA
4. Materials Design Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University 4 , Linköping SE-581 83, Sweden