Thermal conductivity and electrical resistivity of solid iron at Earth's core conditions from first-principles

TL;DR

This study uses first-principles calculations to determine the thermal conductivity and electrical resistivity of solid iron under Earth's core conditions, highlighting the importance of electron-electron scattering and providing updated estimates supporting thermal convection-driven geodynamo models.

Contribution

First-principles calculations reveal significant electron-electron scattering effects on iron's properties at core conditions, updating previous estimates of thermal conductivity.

Findings

Thermal conductivity of outer core iron is estimated at 77±10 W/m/K.

Electrical resistivity shows a quasi-linear relation with temperature.

Electron-electron scattering significantly reduces thermal conductivity estimates.

Abstract

We compute the thermal conductivity and electrical resistivity of solid hcp Fe to pressures and temperatures of Earth's core. We find significant contributions from electron-electron scattering, usually neglected at high temperatures in transition metals. Our calculations show a quasi-linear relation between electrical resistivity and temperature for hcp Fe at extreme high pressures. We obtain thermal and electrical conductivities that are consistent with experiments considering reasonable error. The predicted thermal conductivity is reduced from previous estimates that neglect electron-electron scattering. Our estimated thermal conductivity for the outer core is 77$\pm$10 W/m/K, and is consistent with a geodynamo driven by thermal convection.