1. Key Lab of Microsystem
and Microstructure of Ministry of Education, Harbin Institute of Technology, Harbin 150080, China
2. Department of Physics, Harbin Institute of Technology, Harbin 150080, China
3. Condensed Matter Science and
Technology Institute, Harbin Institute of Technology, Harbin 150080, China
4. Key Laboratory of
Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China