Oxygen-driven enhancement of electron correlation in hexagonal iron at Earth's inner core conditions

TL;DR

This study uses advanced computational methods to show that oxygen stabilizes hexagonal iron in Earth's inner core, significantly affecting its electrical and seismic properties, which supports existing geophysical models.

Contribution

It demonstrates oxygen's role in stabilizing hexagonal iron at core conditions using density functional theory and dynamical mean field theory, providing new insights into Earth's inner core composition.

Findings

Oxygen stabilizes hexagonal iron at core conditions.

Electrical resistivity of oxygen-rich iron is significantly higher.

Seismic velocity calculations match geophysical observations.

Abstract

Earth's inner core consists of mainly iron with a bit of light elements. Understanding of its structure and related physical properties has been elusive for both experiment and theory due to its required extremely high pressure and temperature conditions. Here, using density functional theory plus dynamical mean field theory, we demonstrate that oxygen atoms energetically stabilize hexagonal structured iron at the inner core condition. Electrical resistivity is much enhanced compared with pure hcp-Fe, supporting the conventional thermal convection model. Moreover, our calculated seismic velocity shows a quantitative match with geologically observed Preliminary Reference Earth Model data.