Structural transition and re-emergence of iron's total electron spin in (Mg,Fe)O at ultrahigh pressure.

ABSTRACT: Fe-bearing MgO [(Mg_1-xFe_x)O] is considered a major constituent of terrestrial exoplanets. Crystallizing in the B1 structure in the Earth's lower mantle, (Mg_1-xFe_x)O undergoes a high-spin (S = 2) to low-spin (S = 0) transition at ∼45 GPa, accompanied by anomalous changes of this mineral's physical properties, while the intermediate-spin (S = 1) state has not been observed. In this work, we investigate (Mg_1-xFe_x)O (x ≤ 0.25) up to 1.8 TPa via first-principles calculations. Our calculations indicate that (Mg_1-xFe_x)O undergoes a simultaneous structural and spin transition at ∼0.6 TPa, from the B1 phase low-spin state to the B2 phase intermediate-spin state, with Fe's total electron spin S re-emerging from 0

SUBMITTER: Hsu H 

PROVIDER: S-EPMC9120148 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature