1. Department
of Physics and Astronomy, University of California, Irvine, California 92697, United States
2. School
of Mechanical Engineering and Jiangsu Key Laboratory for Design and
Manufacture of Micro-Nano Biomedical Instruments, Southeast University, Nanjing 211189, China
3. Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
4. Department
of Materials Science, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany