Thermal conductivity of Fe-Si alloys and thermal stratification in Earth's core

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23640%2F21%3A43964072" target="_blank" >RIV/49777513:23640/21:43964072 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1073/pnas.2119001119" target="_blank" >https://doi.org/10.1073/pnas.2119001119</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1073/pnas.2119001119" target="_blank" >10.1073/pnas.2119001119</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Thermal conductivity of Fe-Si alloys and thermal stratification in Earth's core

Popis výsledku v původním jazyce

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 Wm21K21 for liquid Fe-9Si near the topmost outer core. If Earth’s core consists of a large amount of silicon (e.g., &gt; 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. © 2022 National Academy of Sciences. All rights reserved.

Název v anglickém jazyce

Thermal conductivity of Fe-Si alloys and thermal stratification in Earth's core

Popis výsledku anglicky

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 Wm21K21 for liquid Fe-9Si near the topmost outer core. If Earth’s core consists of a large amount of silicon (e.g., &gt; 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. © 2022 National Academy of Sciences. All rights reserved.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

<a href="/cs/project/EF15_003%2F0000358" target="_blank" >EF15_003/0000358: Výpočetní a experimentální design pokročilých materiálů s novými funkcionalitami</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

ISSN

0027-8424

e-ISSN

—

Svazek periodika

119

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

—

Kód UT WoS článku

000748065500006

EID výsledku v databázi Scopus

2-s2.0-85122700628