1. Department
of Physics, University of Trento, Via Sommarive 14 Povo, 38123 Trento, Italy
2. Fondazione Bruno Kessler, Center of Materials and Microsystems, Via Sommarive 18, 38123 Trento, Italy
3. Regional
Centre of Advanced Technologies and Materials, Department of Physical
Chemistry, Palacký University Olomouc, tř. 17. listopadu 12, 771 46 Olomouc, Czech Republic