Probing iron in Earth's core with molecular-spin dynamics

Proc Natl Acad Sci U S A. 2024 Dec 17;121(51):e2408897121. doi: 10.1073/pnas.2408897121. Epub 2024 Dec 12.

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 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.

Keywords: Earth’s interior; dynamical phase transitions; molecular-spin dynamics; shock-physics.