1. NUSNNI-NanoCore, National University of Singapore, 117411 Singapore
2. Department of Physics, National University of Singapore, 117542 Singapore
3. Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States
4. Condensed
Matter Science and Technology Institute, School of Science, Harbin Institute of Technology, Harbin 150081, People’s Republic of China
5. Department of Materials
Science and Engineering, University of California, Berkeley, California 94720, United States
6. School of Physics and CRANN, Trinity College, Dublin 2, Ireland
7. Department of Electrical
and Computer Engineering, National University of Singapore, 117576 Singapore
8. Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore
9. National University of Singapore Graduate School for Integrative Sciences and Engineering (NGS), 28 Medical Drive, Singapore 117456, Singapore