1. Nanoscale Electro-thermal Laboratory, Indian Institute of Information Technology Allahabad, Allahabad, Uttar Pradesh 211015, India
2. Department of Physics, Faculty of Science, University of Ostrava, 30. Dubna 22, 701 03 Ostrava, Czech Republic
3. Electronic Structure Theory Group, Department of Electronics and Communication Engineering, Indian Institute of Information Technology Allahabad, Allahabad, Uttar Pradesh 211015, India