1. Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
2. Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA
3. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
4. Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
5. Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, California 94720, USA