1. State Key Laboratory of Superhard Material and College of Physics, Jilin University, Changchun 130012, P. R. China
2. Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, P. R. China
3. Key Laboratory of Solid State Optoelectronic Devices of Zhejiang Province, College of Physics and Electronic Information Engineering, Zhejiang Normal University, Jinhua, Zhejiang 321004, P. R. China
4. School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China