Document Type
Article
Publication Date
12-12-2018
Publication Title
Physical Review Letters
Volume
121
Issue
25
First page number:
1
Last page number:
6
Abstract
There is compelling geochemical evidence for primordial helium trapped in Earth’s lower mantle, but the origin and nature of the helium source remain elusive due to scarce knowledge on viable helium-bearing compounds that are extremely rare. Here we explore materials physics underlying this prominent challenge. Our structure searches in conjunction with first-principles energetic and thermodynamic calculations uncover a remarkable helium-bearing compound FeO2He at high pressure-temperature conditions relevant to the core-mantle boundary. Calculated sound velocities consistent with seismic data validate FeO2He as a feasible constituent in ultralow velocity zones at the lowermost mantle. These mutually corroborating findings establish the first and hitherto only helium-bearing compound viable at pertinent geophysical conditions, thus providing vital physics mechanisms and materials insights for elucidating the enigmatic helium reservoir in deep Earth.
Disciplines
Physics
File Format
File Size
542 Kb
Language
English
Repository Citation
Zhang, J.,
Lv, J.,
Li, H.,
Feng, X.,
Lu, C.,
Redferm, S. A.,
Liu, H.,
Chen, C.,
Ma, Y.
(2018).
Rare Helium-Bearing Compound FeO2He Stabilized at Deep-Earth Conditions.
Physical Review Letters, 121(25),
1-6.
http://dx.doi.org/10.1103/PhysRevLett.121.255703