Manganese, in the a-Mn structure, has been studied using synchrotron powder x-ray diffraction in a diamond anvil cell up to 220 GPa at room temperature combined with density functional calculations (DFT). The experiment reveals an extended pressure stability of the a-Mn phase up to the highest pressure of this study, in contrast with previous experimental and theoretical studies. On the other hand, calculations reveal that the previously predicted hcp-Mn phase becomes lower in enthalpy than the a-Mn phase above 160 GPa. The apparent discrepancy is explained due to a substantial electron transfer between Mn ions, which stabilizes the a-Mn phase through the formation of ionic bonding between monatomic ions under pressure.
@article{arxiv.2009.11153,
title = {High-pressure structural study of a-Mn: solving a three decades-old mystery},
author = {Logan K. Magad-Weiss and Adebayo A. Adeleke and Eran Greenberg and Vitali B. Prakapenka and Yansun Yao and Elissaios Stavrou},
journal= {arXiv preprint arXiv:2009.11153},
year = {2021}
}