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 (T1) 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.
@article{arxiv.1403.6497,
title = {Electronic correlations determine the phase stability of iron up to the melting temperature},
author = {I. Leonov and A. I. Poteryaev and Yu. N. Gornostyrev and A. I. Lichtenstein and M. I. Katsnelson and V. I. Anisimov and D. Vollhardt},
journal= {arXiv preprint arXiv:1403.6497},
year = {2014}
}