Quasi-particle bands and structural phase transition of iron from Gutzwiller Density-Functional Theory

TL;DR

This study employs Gutzwiller Density Functional Theory to analyze iron's structural phases, accurately predicting properties and phase transition pressures, with results aligning well with experimental data.

Contribution

It introduces a Gutzwiller DFT approach to accurately model iron's ground-state properties and phase transition, improving agreement with experiments.

Findings

Predicted bcc to hcp transition at 41 GPa, close to experimental 10-15 GPa.

Calculated bandstructure matches ARPES data.

Including spin-orbit coupling enhances agreement with experiments.

Abstract

We use the Gutzwiller Density Functional Theory to calculate ground-state properties and bandstructures of iron in its body-centered-cubic (bcc) and hexagonal-close-packed (hcp) phases. For a Hubbard interaction $U=9\, {\rm eV}$ and Hund's-rule coupling $J=0.54\, {\rm eV}$ we reproduce the lattice parameter, magnetic moment, and bulk modulus of bcc iron. For these parameters, bcc is the ground-state lattice structure at ambient pressure up to a pressure of $p_{\rm c}=41\, {\rm GPa}$ where a transition to the non-magnetic hcp structure is predicted, in qualitative agreement with experiment ($p_{\rm c}^{\rm exp}=10\ldots 15\, {\rm GPa}$). The calculated bandstructure for bcc iron is in good agreement with ARPES measurements. The agreement improves when we perturbatively include the spin-orbit coupling.