1. Laboratory for Low Dimensional Materials, Institute of Physics, Bhubaneswar 751005, India
2. Homi Bhaba National Institute, Mumbai 400094, India
3. Computational Materials and Nanoscience Group, Department of Physics and Electronics, St. Xavier’s College, Ahmedabad 380009, India
4. Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
5. Applied Materials Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), S-100 44 Stockholm, Sweden