1. Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology 1 , NO-7491 Trondheim, Norway
2. Departamento de Física, Universidad Técnica Federico Santa María 2 , Casilla 110, Valparaíso, Chile
3. Nordita, KTH Royal Institute of Technology and Stockholm University 3 , Hannes Alfvéns väg 12, SE-106 91 Stockholm, Sweden
4. Department of Computer Science, Electrical Engineering and Mathematical Sciences, Western Norway University of Applied Sciences 4 , NO-5528 Haugesund, Norway