Structures and Metallic transition in Hydrogen under Ultra-High Pressure : Structures come out through Quasi-particle calculations for the electronic band structure

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400371
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Osaka University (2015); Tottori University (2013-2014)
• Principal Investigator: NAGARA Hitose 大阪大学, 基礎工学研究科, 教授 (10135676)
• Co-Investigator(Renkei-kenkyūsha): KOTANI Takao 鳥取大学, 大学院工学研究科, 教授 (60283826) ; ISHIKAWA Takahiro 大阪大学, 基礎工学研究科, 特任助教 (40423082)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 金属水素 / 超高圧縮固体 / 計算物理 / GW近似計算

Outline of Final Research Achievements

Using the band structure calculations based on the quasi-particle picture, i.e. GW approximation, we have studied the pressure dependences of the bandgaps in hydrogen with the structures expected in the pressure range from 200GPa to 400GPa. Combined with the enthalpy data, we obatined the possible structures and their metallization pressure.
Our results show that, at pressures below 280GPa, C2/c-24 structure will be realized and it is insulating. At around 280GPa the Cmca-12 structure will replace the C2/c-24 structure, and the hydrogen becomes metallic because, the band gaps of the Cmca-12 at 280GPa are already closed at 280GPa. The Cmca-12 structure transforms into the metallic Cmca-4 structure at around 380GPa. Acording to this study, the compressed hydrogen becomes metallic by the transfomation into the Cmca-12 structure around 280 GPa, above which pressure hydrogen remains metallic.

Free Research Field

物性物理学