1. Center for High Pressure Science & Technology Advanced Research, 1690 Cailun Rd, Pudong, Shanghai 201203, China.
2. School of Physics and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3JZ, UK.
3. Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198, Japan.
4. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, China.