@article{
doi:10.1073/pnas.2119001119,
author = {Youjun Zhang  and Kai Luo  and Mingqiang Hou  and Peter Driscoll  and Nilesh P. Salke  and Ján Minár  and Vitali B. Prakapenka  and Eran Greenberg  and Russell J. Hemley  and R. E. Cohen  and Jung-Fu Lin },
title = {Thermal conductivity of Fe-Si alloys and thermal stratification in Earth’s core},
journal = {Proceedings of the National Academy of Sciences},
volume = {119},
number = {1},
pages = {e2119001119},
year = {2022},
doi = {10.1073/pnas.2119001119},
URL = {https://www.pnas.org/doi/abs/10.1073/pnas.2119001119},
eprint = {https://www.pnas.org/doi/pdf/10.1073/pnas.2119001119},
abstract = {Light elements in Earth’s core play a key role in driving convection and influencing geodynamics, both of which are crucial to the geodynamo. However, the thermal transport properties of iron alloys at high-pressure and -temperature conditions remain uncertain. Here we investigate the transport properties of solid hexagonal close-packed and liquid Fe-Si alloys with 4.3 and 9.0 wt \% Si at high pressure and temperature using laser-heated diamond anvil cell experiments and first-principles molecular dynamics and dynamical mean field theory calculations. In contrast to the case of Fe, Si impurity scattering gradually dominates the total scattering in Fe-Si alloys with increasing Si concentration, leading to temperature independence of the resistivity and less electron–electron contribution to the conductivity in Fe-9Si. Our results show a thermal conductivity of ∼100 to 110 W⋅m−1⋅K−1 for liquid Fe-9Si near the topmost outer core. If Earth’s core consists of a large amount of silicon (e.g., \> 4.3 wt \%) with such a high thermal conductivity, a subadiabatic heat flow across the core–mantle boundary is likely, leaving a 400- to 500-km-deep thermally stratified layer below the core–mantle boundary, and challenges proposed thermal convection in Fe-Si liquid outer core.}}