1. Physics Department, Charuchandra College, Kolkata 700029, India
2. Condensed Matter Physics Research Centre, Jadavpur University, Kolkata 700032, India
3. Physics Department, St. Xavier’s College, Kolkata 700016, India
4. Mathematical Sciences, Montana Tech, Butte, Montana 59701, USA
5. Physics Department, Chandigarh University, Punjab 140413, India