1. Extreme Conditions Physics Research Laboratory (ECPRL) and Physics of Energy Materials Research Unit Department of Physics Faculty of Science Chulalongkorn University 10330 Bangkok Thailand
2. Thailand Center of Excellence in Physics Commission on Higher Education 328 Si Ayutthaya Road Bangkok 10400 Thailand
3. Center for High Pressure Science and Technology Advanced Research Beijing 100094 People's Republic of China
4. Condensed Matter Theory Group Department of Physics and Astronomy Uppsala University Box 516 S-751 20 Uppsala Sweden
5. Applied Materials Physics Department of Materials and Engineering Royal Institute of Technology (KTH) S-100 44 Stockholm Sweden