1. a International Centre for Materials Science and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur PO, Bangalore 560064 , India
2. b Solid State and Structural Chemistry Unit , Indian Institute of Science , Bangalore 560012 , India
3. c Department of Physics , Indian Institute of Science , Bangalore 560012 , India
4. d Theoretical Science Unit , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur PO, Bangalore 560064 , India