1. Department of Physics and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
2. Nanosystems
Initiative
Munich (NIM), Schellingstr. 4, 80799 Munich, Germany
3. Department of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion — Israel Institute of Technology, 32000 Haifa, Israel
4. Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, United States
5. Institute of Fundamental and Frontier Sciences and State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China