1. Department of Applied Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
2. KTH Royal Institute of Technology, School of Information and Communication Technology, Materials Physics, Kista-Stockholm, Sweden
3. Faculty of Electrical and Computer Engineering, K. N. Toosi University of Technology, Tehran 16314, Iran
4. CIC nanoGUNE Consolider, 20018 Donostia-San Sebastián, Spain
5. Centro de Fisica de Materiales (CSIC—UPV/EHU) and Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
6. CIN2 (ICN-CSIC) and Universitat Autònoma de Barcelona, Catalan Institute of Nanotechnology (ICN), Campus UAB, 08193 Bellaterra (Barcelona), Spain
7. Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
8. IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
9. Department of Physics, University of Gothenburg, 41296 Gothenburg, Sweden