First principle study of vanadium doped ZnS: Structural, electronic, elastic, magnetic and optical properties using mBJ approximation

The structural, electronic, magnetic, mechanical and optical properties of ternary Zn1−xVxS (x = 0.0, 0.25, 0.50, 0.75 and 1.0) ferromagnetic semiconductor alloys have been studied in the zinc blende (ZB) phase, by first principle approach. Density functional theory has been employed to calculate the fundamental properties of the alloys using full-potential linearized augmented plane-wave plus the local orbitals (FP-LAPW + Lo) method. In addition, the electronic and magnetic properties are investigated by the local spin density approximation coupled with the modified Becke–Johnson exchange potential (mBJLDA). Structural analysis revealed that the structure of the three alloys Zn0.75V0.25S, Zn0.50V0.50S, and Zn0.25V0.75S are stable in the ferromagnetic phase. It is noted that the calculated lattice constant decreases, while the bulk modulus increases with the increase of V content. The density of states and spin polarized band structure investigation demonstrated the half-metallic ferromagnetic characteristics of the investigated alloys and are also used to determines p–d exchange constants N0α and N0β, due to S (p)–V(3d) hybridization. These results reveal that magnetic moment of V dopant element reduced from its free space value of 3 μB, because the Zn and S sites acquire minor atomic magnetic moments. The energy band gap analysis show an increasing trend with V doping that makes our compound a suitable candidate for the fabrication of devices operating in the ultraviolet region. Moreover, the static dielectric constant, ε1 (ω), and static refractive index, n (ω), increases with V contents. The incorporation of V generates some new peaks in the energy regions of 0–2.83 eV and 4–10 eV. The substitution by V increases the intensity of the peaks, and a slight red shift has been observed in the absorption peak. The extinction coefficient k (ω) and optical conductivity also follow a similar trend to that of the dielectric constants. These results give deep insight into the design of devices for optical and spintronics applications using V doped ZnS.