1. Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan
2. Computational Atomic-scale Materials Design (CAMD), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
3. Faculty of Physics, University of Vienna, Strudlhofgasse 4, A-1090 Vienna, Austria
4. Key Laboratory of Applied Surface and Colloid Chemistry, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710119, P. R. China
5. The Institute of Scientific and Industrial Research (ISIR-SANKEN), Osaka University, Ibaraki 567-0047, Japan
6. Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark