1. Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
2. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
3. Center for High Pressure Science and Technology Advanced Research, Beijing 100094, P. R. China
4. School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China