1. Hunan
Key Laboratory for Super-microstructure and Ultrafast Process, School
of Physics and Electronics, Central South University, Changsha 410083, China
2. School
of New Energy Science and Engineering, Xinyu University, Xinyu 338004, China
3. Key
Laboratory of Advanced Transducers and Intelligent Control System
(Ministry of Education), Taiyuan University of Technology, Taiyuan 030024, China
4. Department
of Physics and Astronomy, University of Rochester, Rochester, New York 14627, United States