Ferromagnetic and antiferromagnetic spin fluctuations and superconductivity in the hcp-phase of Fe

Abstract

High purity iron, which transforms into the hcp phase under pressure, has recently been reported to be superconducting in the pressure range 150–300 kBar [1]. The electronic structure and the electron–phonon coupling ( λ ph) are calculated for hcp iron at different volumes. A parameter-free theory for calculating the coupling constants λ sf from ferromagnetic (FM) and antiferromagnetic (AFM) spin fluctuations is developed. The calculated λ sf are sufficiently large to explain superconductivity especially from FM fluctuations. The results indicate that superconductivity mediated by spin fluctuations is more likely than from electron–phonon interaction.