The electronic, magnetic and optical properties of Co doped marcasite FeS2

Abstract

The electronic, magnetic and optical properties of Co doped marcasite FeS2 compounds have been investigated through the first-principles calculations. No imaginary frequency emerges in the phonon dispersion curves confirms the Fe7CoS16 and Fe6Co2S16 compounds are dynamical stable. Although the pure Fe8S16 compound is a nonmagnetic semiconductor with band gap of 1.17 eV, the Fe7CoS16 compound changes to a magnetic semiconductor with a very narrow band gap of 0.106 eV, the Fe6Co2S16 compound changes to a half-metal with half-metal band gap of 0.37 eV in spin-down channel. For all three considered configurations of the Fe6Co2S16 compound, the ferromagnetic state is preferred over antiferromagnetic state, especially for smaller separation distance of two doped Co atoms. The higher Curie temperatures than room temperature indicates the Fe6Co2S16 compound is a promising candidate for spintronics applications. In addition, the calculated optical properties shows that Fe7CoS16 and Fe6Co2S16 compounds have stronger absorption than Fe8S16 compound when the wavelength more than 500 nm, which suggests the compounds are potential candidates for solar cells.