التفاصيل البيبلوغرافية
| العنوان: |
PBE-GGA predicts the B8↔B2 phase boundary of FeO at Earth’s core conditions. |
| المؤلفون: |
Zhen Zhang1, Yang Suna2, Wentzcovitch, Renata M.1,3,4,5 rmw2150@columbia.edu |
| المصدر: |
Proceedings of the National Academy of Sciences of the United States of America. 7/11/2023, Vol. 120 Issue 28, p1-6. 17p. |
| مصطلحات موضوعية: |
*EARTH'S core, *THERMODYNAMICS, *AB-initio calculations, *ELECTRONIC excitation, *DENSITY functional theory |
| مستخلص: |
FeO is a crucial component of the Earth’s core, and its thermodynamic properties are essential to developing more accurate core models. It is also a notorious correlated insu- lator in the NaCl-type (B1) phase at ambient conditions. It undergoes two polymorphic transitions at 300 K before it becomes metallic in the NiAs-type (B8) structure at ~100 GPa. Although its phase diagram is not fully mapped, it is well established that the B8 phase transforms to the CsCl-type (B2) phase at core pressures and temperatures. Here, we report a successful ab initio calculation of the B8↔B2 phase boundary in FeO at Earth’s core pressures. We show that fully anharmonic free energies computed with the Perdew–Burke–Ernzerhof-generalized gradient approximation coupled with thermal electronic excitations reproduce the experimental phase boundary within uncertainties at P > 255 GPa, including the largely negative Clapeyron slope of –52 MPa/K. This study validates the applicability of a standard density functional theory functional to FeO under Earth’s core conditions and demonstrates the theoretical framework that enables complex predictive studies of this region. [ABSTRACT FROM AUTHOR] |
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