Electronic structure, optical and elastic properties of AgAlS2 crystal under hydrostatic pressure

In this work, the influence of hydrostatic pressure on the structural, electronic, optical, and mechanical properties of chalcopyrite AgAlS2 crystal was investigated by the first-principles density functional theory calculations. The lattice parameters and unit cell volume decrease with the hydrostatic pressure leading to an increase in the total energy of the crystal. Shown, the bandgap value increases with the pressure while the general peculiarities of the band structure remain almost unchanged. The baric dependences of the real and imaginary parts of the dielectric function are constructed and their analysis is carried out. Several elastic parameters of the material are calculated, such as elastic coefficients C-ij, modulus of elasticity B, shear modulus G, Young's modulus E, Poisson's ratio v. Calculated bulk modulus is consistent with previous theoretical study. The spatial distribution of elastic coefficients and their planar projections are constructed and it is shown that hydrostatic pressure leads to an increase in their anisotropy. It is shown that the modulus of elasticity B has the smallest anisotropy, while the largest is observed for the shear modulus G.