MR016-0006
Spin State and Structural Stability of Ferropericlase up to 30 Mbar

Wednesday, 16 December 2020
Poster
Tianqi Wan, Columbia University, Applied Physics and Applied Mathematics, New York, NY, United States, Yang Sun, Columbia University of New York, Earth and Environmental Sciences, New York, NY, United States and Renata Wentzcovitch, Columbia University in the City of New York, Department of Applied Physics and Applied Mathematics, New York, NY, United States
Abstract:
Ferropericlase (Fp), (Mg1-xFex)O, the second most abundant mineral in the Earth mantle, is expected to be an essential component of the deep mantle of terrestrial super-Earths. Thus, an understanding of Fp across a wide range of pressure, temperature, and iron concentrations is crucial to model the internal structure and dynamics of terrestrial exoplanets. Understanding pressure-induced electronic spin transitions in iron in Fp is a challenging problem given the strongly correlated nature of iron. Here, we present an LDA+Usc study of the structure and magnetic ground state of Fp from 200 GPa to 3 TPa in a range of iron concentrations, xFe, varying from ~3% to 25%. The quasiharmonic approximation (QHA) is used to compute the free energy and stability field of the B1 an B2 phases, as well as thermodynamic properties of these phases up to 3 Mbar. Such properties will be useful modeling the mantle of super-Earth-type planets.

Research supported by NSF grant EAR-1918126

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