1. Department of Physics, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
2. School of Nano Science and Technology, Indian Institute of Technology Kharagpur, West Bengal 721302, India
3. International Centre for Material Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
4. Department of Physics, Indian Institute of Technology Kharagpur, West Bengal 721302, India