Jingyi Zhuang

• Doctor of Philosophy
• Graduate Research Assistant at Columbia University

Iron partitioning among the main lower mantle phases, bridgmanite (Bm) and ferropericlase (Fp), has non‐monotonic behavior owing to the high‐spin to low‐spin crossover in ferrous iron (Fe²⁺) in Fp. Previously reported iron partitioning coefficient between these phases, KD ${K}_{D}$, still have considerable uncertainty. Here, we investigate the Fe²⁺...

Iron partitioning among the main lower mantle phases, bridgmanite (Bm) and ferropericlase (Fp), has non-monotonic behavior owing to the high-spin to low-spin crossover in ferrous iron (Fe2+) in Fp. Results of previous studies of the iron partitioning coefficient between these phases, KD, still have considerable uncertainty. Here, we investigate the...

Three-dimensional models of Earth’s seismic structure can be used to identify temperature-dependent phenomena, including mineralogical phase and spin transformations, that are obscured in 1-D spherical averages. Full-waveform tomography maps seismic wave-speeds inside the Earth in three dimensions, at a higher resolution than classical methods. By...

The quasi-harmonic approximation (QHA) is a powerful method that uses the volume dependence of non-interacting phonons to compute the free energy of materials at high pressures (P) and temperatures (T). However, anharmonicity, electronic excitations in metals, or both, introduce an intrinsic T-dependence on phonon frequencies, rendering the QHA ina...

Joint interpretation of bulk and shear wave speeds constrains the chemistry of the deep mantle. At all depths the diversity of wave speeds cannot be explained by an isochemical mantle. Between 1000 and 2500 km depth, hypothetical mantle models containing an electronic spin crossover in (Mg,Fe)O provide a significantly better fit to the wave-speed d...

The quasi-harmonic approximation (QHA) is a powerful method that uses the volume dependence of non-interacting phonons to compute the free energy of materials at high pressures (P) and temperatures (T). However, anharmonicity, electronic excitations in metals, or both, introduce an intrinsic T-dependence on phonon frequencies, rendering the QHA ina...

The primary phase of the Earth’s lower mantle, (Al, Fe)‐bearing bridgmanite, transitions to the post‐perovskite (PPv) phase at Earth’s deep mantle conditions. Despite extensive experimental and ab initio investigations, there are still important aspects of this transformation that need clarification. Here, we address this transition in (Al³⁺, Fe³⁺)...

In this work, we introduce an open-source Julia project, express, an extensible, lightweight, high-throughput, high-level workflow framework that aims to automate ab initio calculations for the materials science community. express is shipped with well-tested workflow templates, including structure optimization, equation of state (EOS) fitting, phon...

The primary phase of the Earth's lower mantle, (Al, Fe)-bearing bridgmanite, transitions to the postperovskite (PPv) phase at Earth's deep mantle conditions. Despite extensive experimental and ab initio investigations, there are still important aspects of this transformation that need clarification. Here, we address this transition in (Al3+, Fe3+)-...

We present LDA + U sc calculations of high-spin (HS) and low-spin (LS) states in ferropericlase (fp) with an iron concentration of 18.75%. The Hubbard parameter U is determined self-consistently with structures optimized at arbitrary pressures. We confirm a strong dependence of U on the pressure and spin state. Static calculations confirm that the...

We present LDA+$U_{sc}$ calculations of high-spin (HS) and low-spin (LS) states in ferropericlase (fp) with an iron concentration of 18.75$\%$. The Hubbard parameter $U$ is determined self-consistently with structures optimized at arbitrary pressures. We confirm a strong dependence of $U$ on the pressure and spin state. Static calculations confirm...

In this work, we introduce an open-source $\texttt{Julia}$ project, $\texttt{express}$, an extensible, high-throughput, high-level workflow framework that aims to automate $\textit{ab initio}$ calculations for the materials science community. $\texttt{Express}$ is shipped with well-tested workflow templates, including structure optimization, equati...

The thermodynamic properties of hexagonal-close-packed iron (ε−Fe) are essential for investigating the internal structure and dynamic properties of planetary cores. Despite their importance to planetary sciences, experimental investigations of ε−Fe at relevant conditions are still challenging. Therefore, ab initio calculations are crucial to elucid...

The thermodynamic properties of hcp-iron ({\epsilon}-Fe) are essential for investigating planetary cores' internal structure and dynamic properties. Despite their importance to planetary sciences, experimental investigations of {\epsilon}-Fe at relevant conditions are still challenging. Therefore, ab initio calculations can contribute to elucidatin...