Magnetic ground state of face-centered-cubic structure of iron.

First principles calculations reveal that the antiferromagnetic double layer (AFMD) along the magnetization direction of 〈0 0 1〉 is the magnetic ground state of face-centered-cubic (FCC) structure of iron (Fe) due to its lowest total energy among all the studied magnetic states. This magnetic ground state of AFMD-〈0 0 1〉 is fundamentally due to a stronger chemical bonding in terms of electronic structure, and could be confirmed by its mechanical properties for the first time. Calculations also show that lattice constant has an important effect to determine the magnetic state of FCC Fe, and a transition of magnetic state between AFMD-〈0 0 1〉 and ferromagnetic happens at the critical lattice constant of 3.666 Å. The derived results are in good agreement with experimental and theoretical observations, and could clarify the controversy regarding magnetic ground state of FCC Fe in the literature.