1. Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona 08193, Spain
2. Institut für Chemie und Biochemie, Physikalische und Theoretische Chemie, Freie Universität Berlin, Arnimallee 22, Berlin 14195, Germany
3. CNR Institute for Microelectronics and Microsystems (CNR-IMM), Zona Industriale, Strada VIII, 5, Catania 95121, Italy
4. Computing Center, Technical University of Denmark, Kongens Lyngby DK-2800, Denmark
5. Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
6. Department of Physics, Technical University of Denmark, Kongens Lyngby DK-2800, Denmark
7. Center for Nanostructured Graphene (CNG), Kongens Lyngby DK-2800, Denmark
8. ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona 08070, Spain