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.
@article{arxiv.2104.07700,
title = {Unconventional iron-magnesium compounds at terapascal pressures},
author = {Yimei Fang and Yang Sun and Renhai Wang and Feng Zheng and Shunqing Wu and Cai-Zhuang Wang and Renata M. Wentzcovitch and Kai-Ming Ho},
journal= {arXiv preprint arXiv:2104.07700},
year = {2021}
}