Prof. Katsuya Shimizu's group at KYOKUGEN, Osaka University

Phase Boundary of Hot Dense Hydrogen by Transport Measurements

The technical part of our latest developments to generate Mbar pressures and to perform transport measurements in DAC will be presented, showing an observation of a highly conductive hydrogen under high temperature and high-pressure conditions as the example. Hydrogen was compressed then heated with a small gold foil (absorber) and the resistance was monitored by electrical probes deposit on the diamond surface close to the absorber. The temperature dependence of the resistance abruptly decreased at the boundary T - P condition and reached the comparable value to that of previous report [S. T. Weir et al., Phys. Rev. Lett. B 16, 662 (1996)].

(Employment)

Apr. 2014 - Present: Professor, Center for Science and Technology under Extreme Conditions, Osaka University

Apr. 2003 - Mar. 2014: Professor, Center for Quantum Science and Technology under Extreme Conditions, Osaka University

Apr. 2002 - Mar. 2003: Lecturer, Division of Materials Physics, Graduate School of Engineering Science, Osaka University

Apr. 1997 - Mar. 2002: Research Assistant, Division of Materials Physics, Graduate School of Engineering Science, Osaka University

Apr. 1995 - Mar. 1997: Research Fellow of the Japan Society for the Promotion of Science for Young Scientists

(Education)

Mar. 1994: Ph.D, Osaka University (Science)

Mar. 1991: M.E., Faculty of Engineering Science, Osaka University

Mar. 1989: B.E., Engineering Science, Osaka University

Dr. Mari EINAGA

Formation Process of High-Tc Superconducting Phase of Sulfur Hydride

Mari will talk about the recent experimental progress on the high-Tc superconducting phase in hydrogen sulfide under high pressure, Tc ~ 200 K at 150 GPa, discovered by Eremets group in Germany [A. Drozdov et al., Nature 525, 73 (2015)]. This material broke the record for Tc by more than 30 K, which was the first increase in 20 years. We collaborated with Eremets group and investigated its crystal structure using synchrotron

diffraction measurement with electrical resistance measurement in SPring-8. Furthermore, we concentrate on revealing the formation process of the high-Tc phase on the cold compression pathway of the synthesis from molecular H2S.

(Employment)

Apr. 2016 - Present: Specially Appointed Assistant Professor, Center for Science and Technology under Extreme Conditions, Osaka University

Apr. 2014 - Mar. 2016: Specially Appointed Researcher, Center for Science and Technology under Extreme Conditions, Osaka University

Apr. 2013 - Mar. 2014: Specially Appointed Researcher, Center for Quantum Science and Technology under Extreme Conditions, Osaka University

Apr. 2012 - Mar. 2013: Research Fellow of the Japan Society for the Promotion of Science for Young Scientists

(Education)

Mar. 2013: Ph.D, Niigata University (Science)

Mar. 2010: M.E., Graduate School of Science and Technology, Niigata University

Mar. 2008: B.E., Faculty of Science, Niigata University

Mr. Dezhong Meng

Superconductivity of hydrogen-rich metal hydride under high pressure

Dezhong will present the investigation of so-called "hydrogen-rich" metal hydrides, Li5MoH11 with 11 hydrogens in the unit cell. The similar hydrides BaReH9 was reported to be superconductor with a transition temperature (Tc) near 7 K above 100 GPa [T. Muramatu et al., J. Phys. Chem. C 119, 18007 (2015)]. The valence band of Li5MoH11 is dominated by the hydrogen 1s orbital [S. Takagi et al., Sci. Rep. 7, 44253 (2017)]. Thus, Li5MoH11 can be expected to show the metallization and possible high-Tc superconductivity, whose character comes from hydrogen. The observation of superconducting behavior and structural phase transition as a function of pressure about Li5MoH11 will be exhibited.

(Education)

Oct. 2015-Now: Ph.D candidate, Materials Science and Engineering, Osaka University

Jul. 2015: M.E., Materials Science and Engineering, China University of Geosciences (Beijing)

Jul. 2012: B.E., Metallic Materials Engineering, Hebei University of Science and Technology