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Published on: August 17, 2016
Pressure-Induced Metallization of BaH2 and the Effect of Hydrogenation
Hannah A Shuttleworth1, Israel Osmond1, Calum Strain1
1Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH8 8AQ, United Kingdom.
Abstract:
Using optical spectroscopy, X-ray diffraction, and electrical transport measurements, we have studied the pressure-induced metallization in BaH2 and Ba8H46. Our combined measurements suggest a structural phase transition from BaH2-II to BaH2-III accompanied by band gap closure and transformation to a metallic state at 57 GPa. The metallization is confirmed by resistance measurements as a function of the pressure and temperature. We also confirm that, with further hydrogenation, BaH2 forms the previously observed Weaire-Phelan Ba8H46, synthesized at 45 GPa and 1200 K. In this compound, metallization pressure is shifted to 85 GPa. Through a comparison of the properties of these two compounds, a question is raised about the importance of the hydrogen content in the electronic properties of hydride systems.
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