157 / 2025-03-15 22:28:28

Superionic behavior of oxygen-vacant davemaoite and its impact on early mantle oxidation cycle

superionicity,oxygen vacancy,davemaoite,early Earth,oxygen cycle

Davemaoite (CaSiO₃ perovskite), a predominant mineral in Earth’s lower mantle, is known to be formed during the crystallization of early magma ocean. Nevertheless, the influence of oxygen deficiencies on its properties under early mantle conditions has not been extensively studied. In this presentation, I show how oxygen vacancies influence the structural stability and transport behavior of davemaoite by employing machine learning-based molecular dynamics simulations. Our results demonstrate that oxygen diffusion induces a superionic transition, significantly enhancing electrical conductivity. Additionally, elevated concentrations of oxygen vacancies broaden the stability range of the superionic state. These findings imply that oxygen-deficient davemaoite may serve as a principal reservoir and transporter of oxygen within the deep mantle, profoundly affecting deep-Earth oxidation cycles and the redox dynamics of the earth’s early mantle.