Molecular dynamics study of iron at Earth’s inner core condition

1994 ◽  
Author(s):  
Masanori Matsui
Keyword(s):  
Molecular Dynamics ◽  
Inner Core ◽  
Earth’S Inner Core ◽  
Core Condition

scholarly journals Ni Doping: A Viable Route to Make Body-Centered-Cubic Fe Stable at Earth’s Inner Core

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 258
Author(s):  
Swastika Chatterjee ◽  
Sujoy Ghosh ◽  
Tanusri Saha-Dasgupta
Keyword(s):  
Inner Core ◽  
Computational Study ◽  
Stable Phase ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Ni Doping ◽  
Earth’S Inner Core ◽  
Core Condition ◽  
Theoretical Evidence ◽  
The Stability

With the goal of answering the highly debated question of whether the presence of Ni at the Earth’s inner core can make body-centered cubic (bcc) Fe stable, we performed a computational study based on first-principles calculations on bcc, hexagonal closed packed (hcp), and face-centered cubic (fcc) structures of the Fe1−xNix alloys (x = 0, 0.0312, 0.042, 0.0625, 0.084, 0.125, 0.14, 0.175) at 200–364 GPa and investigated their relative stability. Our thorough study reveals that the stability of Ni-doped bcc Fe is crucially dependent on the nature of the distribution of Ni in the Fe matrix. We confirm this observation by considering several possible configurations for a given concentration of Ni doping. Our theoretical evidence suggests that Ni-doped bcc Fe could be a stable phase at the Earth’s inner core condition as compared to its hcp and fcc counterparts.

scholarly journals Two-step nucleation of the Earth’s inner core

2022 ◽  
Vol 119 (2) ◽  
pp. e2113059119
Author(s):  
Yang Sun ◽  
Feng Zhang ◽  
Mikhail I. Mendelev ◽  
Renata M. Wentzcovitch ◽  
Kai-Ming Ho
Keyword(s):  
Molecular Dynamics ◽  
Inner Core ◽  
Nucleation Mechanism ◽  
Body Centered Cubic ◽  
Hexagonal Close Packed ◽  
Key Factor ◽  
Earth’S Inner Core ◽  
Core Conditions ◽  
Dynamics Simulations ◽  
Bcc Phase

The Earth's inner core started forming when molten iron cooled below the melting point. However, the nucleation mechanism, which is a necessary step of crystallization, has not been well understood. Recent studies have found that it requires an unrealistic degree of undercooling to nucleate the stable, hexagonal, close-packed (hcp) phase of iron that is unlikely to be reached under core conditions and age. This contradiction is referred to as the inner core nucleation paradox. Using a persistent embryo method and molecular dynamics simulations, we demonstrate that the metastable, body-centered, cubic (bcc) phase of iron has a much higher nucleation rate than does the hcp phase under inner core conditions. Thus, the bcc nucleation is likely to be the first step of inner core formation, instead of direct nucleation of the hcp phase. This mechanism reduces the required undercooling of iron nucleation, which provides a key factor in solving the inner core nucleation paradox. The two-step nucleation scenario of the inner core also opens an avenue for understanding the structure and anisotropy of the present inner core.

Strong shear softening induced by superionic hydrogen in Earth's inner core

2021 ◽  
Vol 568 ◽  
pp. 117014
Author(s):  
Wenzhong Wang ◽  
Yunguo Li ◽  
John P. Brodholt ◽  
Lidunka Vočadlo ◽  
Michael J. Walter ◽  
...  
Keyword(s):  
Inner Core ◽  
Strong Shear ◽  
Earth’S Inner Core

scholarly journals Melting-induced stratification above the Earth’s inner core due to convective translation

Nature ◽  
2010 ◽  
Vol 466 (7307) ◽  
pp. 744-747 ◽  
Author(s):  
Thierry Alboussière ◽  
Renaud Deguen ◽  
Mickaël Melzani
Keyword(s):  
Inner Core ◽  
Earth’S Inner Core
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