Experimental evidence for superionic Fe-C alloy revealed by shear softening in Earth's inner core.

ABSTRACT: Seismic observations reveal that Earth's inner core is rigid yet displays ultralow shear wave velocities (V _s) and an ultra-high Poisson's ratio (∼0.45). While superionic behavior in iron-light element alloys (e.g. carbon) has been proposed to explain these features, experimental validation has been lacking. Here, we combine dynamic high pressure-temperature (P-T) experiments with ab initio molecular dynamics simulations to investigate the elastic properties and atomic behaviors of hexagonal close-packed (hcp) Fe-1.5 wt% C (Fe-1.5C) alloy under core-like conditions. Theoretical simulations reveal a temperature-induced transition to a superionic state in the hcp-Fe-1.5C alloy above T/T _m ≈ 0.68 (T _m: melting temperature) un

SUBMITTER: Huang Y 

PROVIDER: S-EPMC12598642 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature