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arXiv · 1403.6497

Electronic correlations determine the phase stability of iron up to the melting temperature

I. Leonov·A. I. Poteryaev·Yu. N. Gornostyrev·A. I. Lichtenstein·M. I. Katsnelson·V. I. Anisimov·D. Vollhardt
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Abstract

We present theoretical results on the high-temperature phase stability and phonon spectra of paramagnetic bcc iron which explicitly take into account many-body effects. Several peculiarities, including a pronounced softening of the [110] transverse (T$_1$) mode and a dynamical instability of the bcc lattice in harmonic approximation are identified. We relate these features to the $α$-to-$γ$ and $γ$-to-$δ$ phase transformations in iron. The high-temperature bcc phase is found to be highly anharmonic and appears to be stabilized by the lattice entropy.

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I. Leonov, A. I. Poteryaev, Yu. N. Gornostyrev, A. I. Lichtenstein, M. I. Katsnelson, V. I. Anisimov, D. Vollhardt. 2014-03-25. Electronic correlations determine the phase stability of iron up to the melting temperature. https://doi.org/10.1038/srep05585

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