1. Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, via Arnesano, I-73100 Lecce, Italy
2. Department of Industrial Engineering (DIN), Università di Bologna, Viale del Risorgimento 2, 40123 Bologna, Italy
3. Advanced Mechanics and Materials-Interdepartmental Center, University of Bologna, Viale del Risorgimento 2, 40123 Bologna, Italy
4. NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
5. Chemistry Department “Giacomo Ciamician” and INSTM UdR of Bologna, University of Bologna, via Selmi 2, 40126 Bologna, Italy
6. Department of Mechanical Engineering, Technion − Israel Institute of Technology, Haifa 32000, Israel
7. Health Sciences and Technologies-Interdepartmental Center for Industrial Research (HST-ICIR), University of Bologna, Via Tolara di Sopra 41/E, Ozzano Emilia I-40064, Italy
8. Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy