Work

Ab Initio Study of the Conductivities of B2 FeSi Under Core‐Mantle Boundary Conditions

Year: 2025

Type: article

Abstract: While the ultra‐low velocity zones (ULVZs) may hold key information about deep Earth dynamics, their elusive state and origin remain enigmatic. Recent high‐pressure experiments suggest that ULVZs may originate from the B2 FeSi crystallization from the outer core. Understanding the conductivity of the B2 phase can shed light on its role in deep mantle dynamics and serve as a test for its presence at the core‐mantle boundary (CMB). Here, we calculated the thermal and electrical conductivities of B2 Fe 1‐ x Si x at 127 GPa and up to 4,500 K using first‐principles molecular dynamics. Our results show that under CMB conditions, the thermal and electrical conductivities of B2 FeSi are significantly higher than those of lower‐mantle minerals. The exceptionally high conductivities of B2 FeSi would enhance heat transfer and elevate temperatures within ULVZs, if B2 FeSi is present, thereby promoting the core dynamo and powering hotspots, consistent with seismic observations of ULVZs.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl115024

Authors: Yonghui Huang, Yunguo Li, Dario Alfè, Monica Pozzo, Huaiwei Ni

Institutions: University of Science and Technology of China, Deep Space Exploration Laboratory, University College London, University of Naples Federico II, Mercatorum University

Language: English

Topic: High-pressure geophysics and materials

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,190

Funders: National Natural Science Foundation of China, University of Science and Technology of China, Natural Environment Research Council