Abstract
Rare earth element polyhydrides have been predicted to exhibit high- superconductivity at extreme compressions. Through a series of in situ high-pressure high-temperature x-ray powder diffraction experiments combined with density functional theory calculations, we report the emergence of polyhydride species in the praseodymium-hydrogen system. We initially observe the formation of , which continuously increases in hydrogen content on compression towards . Laser heating in a hydrogen medium at pressures of 85 GPa leads to the synthesis of both and . Both structures are characterized by hexagonal arrays of praseodymium atoms surrounded by hydrogen clathrate cages.
- Received 4 June 2019
- Revised 21 October 2019
DOI:https://doi.org/10.1103/PhysRevB.100.184109
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