Probing Iron in Earth's Core With Molecular-Spin Dynamics

TL;DR

This paper introduces a novel machine-learned molecular-spin dynamics method to study iron under Earth's core conditions, providing insights into phase transitions, elastic properties, and electronic transport relevant to the geodynamo.

Contribution

A new MSD methodology with explicit spin-fluctuation treatment that accurately models iron's behavior at core conditions and couples with DFT for electronic transport analysis.

Findings

Accurate phase-transition kinetics of iron under core conditions

Elastic properties matching seismic measurements

Electronic transport properties relevant to geodynamo

Abstract

Dynamic compression of iron to Earth-core conditions is one of the few ways to gather important elastic and transport properties needed to uncover key mechanisms surrounding the geodynamo effect. Herein a new machine-learned ab-initio derived molecular-spin dynamics (MSD) methodology with explicit treatment for longitudinal spin-fluctuations is utilized to probe the dynamic phase-diagram of iron. This framework uniquely enables an accurate resolution of the phase-transition kinetics and Earth-core elastic properties, as highlighted by compressional wave velocity and adiabatic bulk moduli measurements. In addition, a unique coupling of MSD with time-dependent density functional theory enables gauging electronic transport properties, critically important for resolving geodynamo dynamics.