1. COMP
Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 11000, FI-00076 Aalto, Espoo, Finland
2. Departamento
de Física, Universidade Federal do Rio Grande do Norte, Natal, RN, 59078-900, Brazil
3. Department
of Physics, Oakland University, Rochester, Michigan 48309, United States
4. Department
of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
5. Department
of Mathematical Sciences and Department of Physics, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom