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Electronic temperature driven phase stability and structural evolution of iron at high pressure

S. Azadi1,2,* and S. M. Vinko2,3

  • *Contact author: sam.azadi@physics.ox.ac.uk
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Phys. Rev. B 112, 134103 – Published 23 October, 2025

DOI: https://doi.org/10.1103/tm8g-1ld1

Abstract

We present Gibbs free-energy phase diagrams for compressed iron within a pressure range of 20–300 GPa and electronic temperature up to 3 eV, obtained using finite-temperature density functional and density functional perturbation theories. Our results for bcc, fcc, and hcp phases predict solid-solid phase transitions in iron driven purely by electronic entropy and temperature. We found a phase transition from hcp to bcc at pressures above 200 GPa, which depends on the electronic temperature. An experimental observation of the stability of the bcc phase above 200 GPa has recently been reported (Z. Konopkova et al., arXiv:2505.15397).

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Phys. Rev. B 112, 134103– Published 23 October, 2025
  • Received 2 June 2025
  • Revised 1 September 2025
  • Accepted 9 October 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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