1. State Key Laboratory of Superhard Materials College of Physics Jilin University Changchun 130012 P. R. China
2. Synergetic Extreme Condition User Facility State Key Laboratory of Superhard Materials College of Physics Jilin University Changchun 130012 P. R. China
3. Center for High Pressure Science and Technology Advanced Research Shanghai 211203 P. R. China
4. Center for High Pressure Science (CHiPS) State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao Hebei 066004 P. R. China