Fermi-liquid behavior and thermal conductivity of {\epsilon}-iron at Earth's core conditions

TL;DR

This study investigates the electronic and thermal transport properties of epsilon-iron under Earth's core conditions, revealing Fermi-liquid behavior and a modified Wiedemann-Franz law that impacts Earth's core dynamics.

Contribution

It combines density functional and dynamical mean field theories to analyze electron correlations in epsilon-iron at extreme conditions, highlighting its Fermi-liquid nature and altered thermal conductivity.

Findings

Epsilon-iron behaves as a nearly perfect Fermi liquid.

Thermal conductivity is suppressed compared to electrical conductivity.

Electron-electron thermal resistivity is comparable to electron-phonon resistivity.

Abstract

The electronic state and transport properties of hot dense iron are of the utmost importance to geophysics. Combining the density functional and dynamical mean field theories we study the impact of electron correlations on electrical and thermal resistivity of hexagonal close-packed $\epsilon$-Fe at Earth's core conditions. $\epsilon$-Fe is found to behave as a nearly perfect Fermi liquid. The quadratic dependence of the scattering rate in Fermi liquids leads to a modification of the Wiedemann-Franz law with suppression of the thermal conductivity as compared to the electrical one. This significantly increases the electron-electron thermal resistivity which is found to be of comparable magnitude to the electron-phonon one. The implications of this effect on the dynamics of Earth's core is discussed.