Conductive but poor metallic solid hydrogen
Hydrogen, the most abundant and lightest element in the universe, is the object of fundamental physics research that focuses on its transition to a metallic phase. It has been predicted for decades that metallization in pure hydrogen gives rise to superconductivity with very high transition temperature.
Recently, the existence of metallic solid hydrogen has been reported around 260 GPa , but results of more recent experiments are inconsistent with transition pressure. Rigorous theoretical work will aid our understanding of physical properties of solid hydrogen under pressure. In our study, we used several computational techniques. We predict that solid hydrogen becomes semi-metallic at 260 GPa and low temperature. Under those conditions, the superconductivity transition temperature is near 0.
“Our study predicted that insulating solid hydrogen will undergo a phase transition to a poor metallic state at low temperature. This suggestion indicates that conductance changes at the transition would be smooth than sharp. Alkali-type metallic phase of solid hydrogen would require much higher pressure than tested in our study”, the leading scientist of this study, Duck Young Kim said.
See article: Lebègue, S., C. M. Araujo, D. Y. Kim, M. Ramzan, H.-k. Mao and R. Ahuja, Semimetallic dense hydrogen above 260 GPa. Proc. Natl. Acd. Sci. USA 108:25, 9766-9769 (2012). DOI: 10.1073/pnas.1207065109.