A novel antiferromagnetic semiconductor hidden in pyrite

Abstract

In this paper, a new two-dimensional antiferromagnetic material, 2D pyrite, was reported, which exhibited a completely planar pentagonal structure. Pentagonal FeS2 were revealed by the first-principles calculation with GGA + U (Ueff = 2 eV) method and proved excellent mechanically stable, dynamically stable and thermally stable. Intriguingly, this single-layer structure was perfectly in line with the geometric characteristic of “Cairo pentagon”. Completely different from the bulk pyrite, the two-dimensional FeS2 was proved an amazing magnetic semiconductor and the ground state configuration of the magnetic coupling is antiferromagnetic with a 0.31 eV band gap. Considering the spin–orbit coupling effect, the magnetocrystalline anisotropy energy (MAE) in different orientation was calculated and the easy axis was proved along the c axis. The highest MAE in our GGA + U calculation could reach 454.77 μeV per Fe atom. Furthermore, biaxial strain was applied to regulate the electronic structure of 2D FeS2 and the results suggested that 2D pyrite would be converted into ferromagnetic configuration when the strain ranging from 2.2% to 5.0%. Therefore, our research predicted a new two-dimensional spintronic materials and proved a new thought for the application of pyrite.