Strain Effects on the Band Structures of Monolayer GaN from the Density Functional Theory

We perform the density functional theory calculations (DFT) to study the effect of biaxial strain on the band structures of monolayer GaN. We apply compressive and tensile strains up to 10%. There is no change of bandgap for the applied tensile strains below 8%. The compressive strains have a constant bandgap which is slightly smaller than that of the zero strain. We find that the applied tensile strain above 8% affects its electronic structure and decreases its bandgap energy by about 0.05 eV while the compressive strain above 4% decreases its bandgap about 0.22 eV.