First-principles studies of pressure dependence of elastic and electronic properties in filled tetrahedral semiconductors LiMgX (X=N, P, and As)

The elastic and electronic properties of the filled tetrahedral semiconductors LiMgX (X=N, P, As) under pressure effect have been investigated using the pseudo-potential plane wave method within density functional theory. The equilibrium lattice constant of LiMgX compounds were calculated. A numerical first-principles calculation of the elastic constants was used to calculate C11, C12, C44 and their pressure derivatives. Band structure, density of states and pressure dependence of band gaps were investigated. The results are compared with the available theoretical and experimental data.