1. School of Natural Sciences (SNS), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
2. Salam Chair in Physics, Department of Physics, GC University Lahore, Lahore 54000, Pakistan
3. Department of Physics, GC University Lahore, Lahore 54000, Pakistan
4. Department of Physics, COMSATS Institute of Information Technology, Lahore 54000, Pakistan