1. Department of Physics, Kırıkkale University, Kırıkkale 71450, Turkey
2. Department of Physics, Adnan Menderes University, 09100 Aydin, Turkey
3. Materials Science and Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
4. Department of Electrical and Electronic Engineering, Bilkent University, Ankara 06800, Turkey
5. Department of Physics, Bilkent University, Ankara 06800, Turkey
6. Department of Natural and Mathematical Sciences, Ozyegin University, Istanbul 34794, Turkey
7. Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
8. Physik Department E20, Technische Universität München, 85748 Garching, Germany