1. Department of Physics, Jadavpur University, Kolkata 700032, India
2. St. Thomas’ College of Engineering & Technology, Kolkata 700023, India
3. School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700032, India
4. Basque Center for Applied Mathematics, Alameda de Mazarredo, 14, E-48009 Bilbao, Spain