1. Theoretical Division,
Center for Nonlinear Studies and Center for Integrated Nanotechnologies,
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
2. Department
of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
3. School
of Chemistry, Physics and Mechanical Engineering Faculty, Queensland University of Technology, Garden Point Campus, QLD 4001, Brisbane, Australia