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arXiv · 2104.07700

Unconventional iron-magnesium compounds at terapascal pressures

Yimei Fang·Yang Sun·Renhai Wang·Feng Zheng·Shunqing Wu·Cai-Zhuang Wang·Renata M. Wentzcovitch·Kai-Ming Ho
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Abstract

Being a lithophile element at ambient pressure, magnesium is long believed to be immiscible with iron. A recent study by Gao et al. [1] showed that pressure turns magnesium into a siderophile element and can produce unconventional Fe-Mg compounds. Here, we extend the investigation to exoplanetary pressure conditions using an adaptive genetic algorithm-based variable-composition structural prediction approach. We identify several Fe-Mg phases up to 3 TPa. Our cluster alignment analysis reveals that most of the predicted Fe-Mg compounds prefer a BCC packing motif at terapascal pressures. This study provides a more comprehensive structure database to support future investigations of the high-pressure structural behavior of Fe-Mg and ternary, quaternary, etc. compounds involving these elements.

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Yimei Fang, Yang Sun, Renhai Wang, Feng Zheng, Shunqing Wu, Cai-Zhuang Wang, Renata M. Wentzcovitch, Kai-Ming Ho. 2021-04-15. Unconventional iron-magnesium compounds at terapascal pressures. https://doi.org/10.1103/physrevb.104.144109

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