1. Department of Solid State Physics, National and Kapodistrian University of Athens, Zografou Panepistimioupolis, 15784 Zografou, Greece
2. Institute of Nanoscience and Nanotechnology, National Center for Scientific Research ‘Demokritos’, 15310 Aghia Paraskevi, Greece
3. Institute for Superconducting and Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, NSW 2500, Australia