Band gap modulation of ZrX₂ (X = S, Se, Te) mono-layers under biaxial strain and transverse electric field and its lattice dynamic properties: a first principles study

The effect of strain on the electronic properties of mono-layers of Zirconium based dichalcoge nides ZrX₂ (X = S, Se, Te) was studied using density functional theory based first-principles calculations. The variation in band gap due to biaxial tensile as well as compressive strain was calculated in these mono-layers. The modulation in band gap on application of external electric field has also been studied and it is observed that it decreases monotonically on applying a transverse electric field. These mono-layers and their strained structure are found to be dynamically stable as observed from their phonon spectrum. The population analysis in these systems indicates that with decreasing strain the d-population of Zr atoms increases whereas the p-population of S, Se, Te atoms decreases. (paper)