1. Research Centre of Materials Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
2. Ibnu Sina Institute
for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 Johor, Malaysia
3. Physics Department, Faculty
of Science, Universiti Teknologi Malaysia, Skudai 81310 Johor, Malaysia
4. Department
of Materials Science and Engineering, Peking University, Beijing 100871, P.R. China