Electronic Band Structure and Optical Response of Spinel SnX₂O₄ (X = Mg, Zn) through Modified Becke–Johnson Potential

The modified Becke–Johnson exchange potential approximation is applied to predict the band structure, optical parameters and electron density of SnMg₂O₄ and SnZn₂O₄. The local density approximation, generalized gradient approximation (GGA), EV-GGA significantly underestimate the direct band gap values compared to modified Becke–Johnson approximation. The band gap dependent optical parameters such as dielectric constant, index of refraction, reflectivity, and optical conductivity are calculated and analyzed. A prominent feature of cation replacement is observed and analyzed for these studied compounds. The replacement of the cation Mg by Zn leads to a significant reduction in the value of band gap and consequently affects its dependant optical parameters. This variation is of crucial importance for device fabrication in different regions of the spectrum.