Spin polarized first principles calculations on electronic, magnetic and optical properties of Zn(1−x)AxS (A = Cr/Mn/Fe) using mBJ approximation

Abstract

A systematic investigation on structural, electronic, magnetic and optical properties of Zn(1−x)AxS (A = Cr/Mn/Fe) are performed using first principles calculations within the frame work of spin polarized density functional theory (SP-DFT) as implemented in WIEN2k. The electronic, magnetic and optical properties are performed using the local spin density approximation (LSDA) coupled with modified Becke Johnson (mBJ) potential. The present results show that Zn(1−x)MnxS systems exhibit semiconducting behaviour whereas a half-metallic character is shown by both Zn(1−x)CrxS and Zn(1−x)FexS systems. Although undoped ZnS is a non-magnetic semiconductor, the calculated spin polarized density of states of Cr2+:ZnS and Fe2+:ZnS show 100% spin polarization at Fermi energy, EF. The optical properties, including the real and imaginary part of dielectric function, reflectivity, refractive index, absorption co-efficient, electron energy loss function and optical conductivity of undoped ZnS and Zn(1−x)AxS (A = Cr/Mn/Fe) systems are calculated using mBJ potential. The substitution of Cr and Fe in ZnS not only influences the position of absorption peaks of parent semiconductor in the UV region, but also leads to the formation of new narrow peaks in the visible and IR regions. A considerable red shift in the absorption peak due to the substitution of Fe and Cr shows a good agreement with the previous theoretical results. These outcomes imply that Zn(1−x)AxS (A = Cr/Fe) systems cover the spectral range from IR to near UV and seem to be the promising candidates for optoelectronic and spintronic applications.