Calculated phonon spectra of paramagnetic iron at the $\alpha$-$\gamma$ phase transition

We compute lattice dynamical properties of iron at the bcc-fcc phase transition using dynamical mean-field theory implemented with the frozen-phonon method. Electronic correlations are found to have a strong effect on the lattice stability of paramagnetic iron in the bcc phase. Our results for the structural phase stability and lattice dynamical properties of iron are in good agreement with experiment.

Figure 1

Phonon dispersion curves and corresponding phonon density of states of paramagnetic bcc Fe as calculated within the nonmagnetic GGA (top) and DMFT (bottom). The DMFT result is further interpolated using a Born–von Kármán model with interactions expanded up to the fifth nearest-neighbor shell. The results are compared with neutron inelastic scattering measurements at 1173 K (Ref. 17).

Figure 2

Phonon dispersion curves and corresponding phonon density of states of paramagnetic fcc Fe as calculated within the nonmagnetic GGA (top) and DMFT (bottom). The DMFT result is further interpolated using a Born–von Kármán model with interactions expanded up to the fifth nearest-neighbor shell. The results are compared with neutron inelastic scattering measurements at 1428 K (Ref. 19).