1. Institute of Engineering Physics, Hanoi University of Science and Technology, 1 Dai Co Viet Rd., Hanoi, Vietnam
2. Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, USA
3. CCS-3, Information Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
4. Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
5. School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Dr. NW, Atlanta, Georgia 30332, USA