Thermal conductivity of Fe-Si alloys and thermal stratification in Earth’s core
Youjun Zhang, Kai Luo, Mingqiang Hou, Peter Driscoll, Nilesh P. Salke, J. Minář, Vitali B. Prakapenka, Eran Greenberg, Russell J. Hemley, R. E. Cohen, Jung‐Fu Lin
Abstract
Significance Earth’s liquid outer core is mainly composed of iron alloyed with ∼8 to 10% of light elements (e.g., silicon). Convection of the liquid core generates Earth’s magnetic field, which is controlled by the thermal conductivity of the core. In this study, we investigated the resistivity and thermal conductivity of iron-silicon alloys as a candidate composition in Earth’s core via high-pressure and -temperature experiments and numerical calculations. We found a near temperature independence of the resistivity in iron-silicon alloys at Earth core’s pressure and thus a high thermal conductivity. This work indicates that if silicon is the sole major light element in Earth’s core it could depress thermal convection and promote a thermally stratified layer at the topmost outer core.