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APAM Fall Faculty Research Conference: Prof Renata M. Wentzcovitch
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Fri, Oct 23, 2026
4 PM – 5 PM EDT (GMT-4)
Private Location (register to display)
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About the October Speaker: Can you guess our next speaker? Her research career started in astronomy/astrophysics and she has been trying (hard) to get back there using atomistic simulations (!!!).
The September speaker is... Professor Renata M. Wentzcovitch!
Title: "Electronic Spin Transitions and Mineral Phase Equilibria at Extreme Conditions"
Abstract: Two decades after its discovery, the bridgmanite (Bm, MgSiO3-perovskite) to post-perovskite (Bm–PPv) transition remains central to our understanding of Earth’s D″ region, the lowermost 300 km of the Earth’s mantle. Yet a persistent paradox remains: the sharp seismic discontinuity spans less than 2 GPa (< 30 km), whereas the phase transition in (Mg1-x,Fex)SiO₃ (x~0.1) extends over 5–10 GPa (~100 km). Combining first-principles free energies, multicomponent phase equilibria, and full-waveform seismic simulations, we resolve this discrepancy by considering the transition within multiphase mantle mineral assemblages. The pressure-induced spin crossover of Fe²⁺ in ferropericlase (Fp), the second most abundant phase in the lower mantle, lowers its chemical potential, drawing iron out of Bm and sharply narrowing the Bm–PPv coexistence interval in pyrolitic and harzburgitic compositions. The resulting seismic signatures depend on composition and may help constrain the chemistry of the lowermost mantle. Fp thus actively shapes the thermodynamic and seismic expression of the transition through its electronic spin state. This work illustrates the predictive power of electronic-structure theory, connecting quantum-scale phenomena to mineral equilibria and observable planetary structure.
Research Supported by the Gordon & Betty Moore Foundation, Award GBMF12801 (doi.org/10.37807/GBMF12801)