Equations of state and stability of MgSiO${}_3$ perovskite and post-perovskite phases from quantum Monte Carlo simulations

Abstract

We have performed quantum Monte Carlo (QMC) simulations and density functional theory (DFT) calculations to study the equations of state of MgSiO${}_3$ perovskite (Pv) and post-perovskite (PPv), up to the pressure and temperature conditions of the base of Earth's lower mantle. The ground state energies were derived using QMC and the temperature dependent Helmholtz free energies were calculated within the quasi-harmonic approximation and density functional perturbation theory. The equations of state for both phases of MgSiO${}_3$ agree well with experiments, and better than those from generalized gradient approximation (GGA) calculations. The Pv-PPv phase boundary calculated from our QMC equations of states is also consistent with experiments, and better than previous LDA calculations. We discuss the implications for double crossing of the Pv-PPv boundary in the Earth.

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Cited by in corpus (6)

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• Towards a systematic assessment of errors in diffusion Monte Carlo calculations of semiconductors: case study of zinc selenide and zinc oxide
• Blocked radiative heat transport in the hot pyrolitic lower mantle
• Interpenetrating Graphene Networks: Three-dimensional Node-line Semimetals with Massive Negative Linear Compressibilities
• Anharmonic thermodynamic properties and phase boundary across the post-perovskite transition in MgSiO${}_3$