Dynamic stabilization of cubic $\mathrm{Ca}\mathrm{Si}{\mathrm{O}}_{3}$ perovskite at high temperatures and pressures from ab initio molecular dynamics

Dynamic stabilization of cubic $Ca Si O_{3}$ perovskite at high temperatures and pressures from ab initio molecular dynamics

Tao Sun, Dong-Bo Zhang, and Renata M. Wentzcovitch

Phys. Rev. B 89, 094109 – Published 26 March 2014

Abstract

The stability of cubic $Ca Si O_{3}$ perovskite (CaPv) at high temperatures and pressures is investigated by vibrational normal-mode analysis. We compute power spectra of mode autocorrelation functions using a recently developed hybrid approach combining ab initio molecular dynamics with lattice dynamics. These power spectra, together with the probability distributions of atomic displacements, indicate that cubic CaPv is stabilized at $T \sim 600$ K and $P \sim$ 26 GPa. We then utilize the concept of phonon quasiparticles to characterize the vibrational properties of cubic CaPv at high temperature and obtain anharmonic phonon dispersions through the whole Brillouin zone. Such temperature-dependent phonon dispersions pave the way for more accurate calculations of free-energy, thermodynamic, and thermoelastic properties of cubic CaPv at Earth's lower mantle conditions.

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Received 10 July 2013
Revised 25 February 2014

DOI:https://doi.org/10.1103/PhysRevB.89.094109

Authors & Affiliations

Tao Sun^1,*, Dong-Bo Zhang¹, and Renata M. Wentzcovitch^1,2,†

¹Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
²Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA

^*Present address: Key Laboratory of Computational Geodynamics, University of Chinese Academy of Sciences, Beijing 100049, China.
^†wentz002@umn.edu.

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Vol. 89, Iss. 9 — 1 March 2014

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Physical Review B

covering condensed matter and materials physics

Dynamic stabilization of cubic $Ca Si O_{3}$ perovskite at high temperatures and pressures from ab initio molecular dynamics

Tao Sun, Dong-Bo Zhang, and Renata M. Wentzcovitch

Phys. Rev. B 89, 094109 – Published 26 March 2014

Abstract

Authors & Affiliations

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Physical Review B

covering condensed matter and materials physics

Dynamic stabilization of cubic Ca Si O 3 perovskite at high temperatures and pressures from ab initio molecular dynamics

Tao Sun, Dong-Bo Zhang, and Renata M. Wentzcovitch

Phys. Rev. B 89, 094109 – Published 26 March 2014

Abstract

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Dynamic stabilization of cubic $Ca Si O_{3}$ perovskite at high temperatures and pressures from ab initio molecular dynamics