1. Physics of Nanodevices, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
2. Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, 01328 Dresden, Germany
3. CNR-SPIN, c/o Università degli Studi di Salerno, I-84084 Fisciano, Italy
4. Dipartimento di Fisica “E. R. Caianiello”, Università degli Studi di Salerno, I-84084 Fisciano, Italy
5. Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
6. Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany
7. School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom