1. Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
2. Department of Physics, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
3. Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
4. Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
5. Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
6. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
7. Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India