1. School of Engineering, Brown University, Providence, Rhode Island 02912, United
States
2. Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, China
3. Trison Business Solutions Inc., 17 Bank Street, Le Roy, New York 14482,
United States
4. General Motors R&D Center, Warren, Michigan 48090, United States
5. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China