1. Department of Quantum Matter Physics University of Geneva 24 Quai Ernest Ansermet Geneva CH‐1211 Switzerland
2. Department of Applied Physics University of Geneva 24 Quai Ernest Ansermet Geneva CH‐1211 Switzerland
3. Department of Chemistry University of Zurich Zurich CH‐8057 Switzerland
4. Dipartimento di Scienze Fisiche Informatiche e Matematiche University of Modena and Reggio Emilia Modena IT‐41125 Italy
5. Centro S3 CNR Istituto Nanoscienze Modena IT‐41125 Italy
6. Research Center for Functional Materials National Institute for Materials Science 1‐1 Namiki Tsukuba 305‐0044 Japan
7. International Center for Materials Nanoarchitectonics National Institute for Materials Science 1‐1 Namiki Tsukuba 305‐0044 Japan