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arXiv · 2405.11810

Formation of Iron-Helium Compounds under High Pressure

Haruki Takezawa·Han Hsu·Kei Hirose·Fumiya Sakai·Suyu Fu·Hitoshi Gomi·Shiro Miwa·Naoya Sakamoto
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Abstract

We report the formations of fcc and distorted hcp iron-helium compounds with x in FeHex up to 0.13 and 0.48, respectively, based on experiments at 5-54 GPa and ~1000-2820 K. Upon releasing pressure under room temperature, these fcc and distorted hcp FeHex were still observed by XRD and SIMS measurements. Our first-principles calculations indicate that fcc and hcp FeHex, with helium atoms occupying the tetrahedral and trigonal-planar interstitial sites (instead of the octahedral sites), are dynamically stable throughout 0-50 GPa. These results support that the Earth's core can be a large reservoir of primordial 3He.

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Haruki Takezawa, Han Hsu, Kei Hirose, Fumiya Sakai, Suyu Fu, Hitoshi Gomi, Shiro Miwa, Naoya Sakamoto. 2024-05-20. Formation of Iron-Helium Compounds under High Pressure. https://arxiv.org/abs/2405.11810

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