Pressure effect on the optical properties of the filled tetrahedral semiconductors LiZnX (X=N,P,andAs)

First principles calculations, by means of the full potential linearized augmented plane wave method within the local density approximation, were carried out for the pressure dependence of the electronic and optical properties of the filled tetrahedral compounds LiZnN, LiZnP and LiZnAs. The first order band gap pressure coefficient aΓ-Γ in LiZnN is larger than the corresponding one in GaN, while it is smaller in LiZnP and LiZnAs compared to the one in GaP and GaAs, respectively. The aΓ-L value in the ternaries is greater than the corresponding one in the binaries. The structures in the optical spectra shift towards higher energies when the pressure increases. The static dielectric function decreases with pressure.