Theoretical study of electronic and optical properties of antiferromagnetic β-MnS using the modified Becke Johnson (mBJ) potential

Abstract

We have investigated the electronic and optical properties of β-MnS with III-type antiferromagnetic ordering using full potential linearized augmented plane wave (FP-LAPW) method within the framework of the spin-polarized density functional theory as implemented in WIEN2k package. Firstly, it is proven that III-type antiferromagnetic ordering is stable in comparison with others from the total energy calculated using the Perdew-Burke-Ernzerhof (PBE) functional. Then, we study the electronic properties of β-MnS for an energy range from −5 eV to 5 eV using mBJ exchange and PBE semilocal correlation, our calculations show an indirect energy band gap of 2.275 eV and the strong hybridization of Mn-3d states and S-3p state in valence band. Additionally, we also investigate the effect of spin-orbit coupling on the electronic properties, this causes a very slight red-shift in both Mn-3d and S-3p states but no change of energy gap is observed. Finally, the linear optical properties such as absortion coefficient, reflectivity, energy loss function, refractive index, extinction coefficient and optical conductivity have been derived from calculated complex dielectric function for energy from 0 eV to 24 eV considering all the three polarization directions (E//x, E//y and E//z). The obtained results indicate that β-MnS is an optically isotropic material when the energy is small and it becomes anisotropic for high energy.