THERMODYNAMIC PROPERTIES OF CuAlS2 WITH CHALCOPYRITE STRUCTURE FROM FIRST-PRINCIPLES CALCULATIONS

We have performed detailed studies of the lattice dynamics and thermodynamic properties of CuAlS2 within the density functional perturbation theory and pseudopotential methods. The results for the phonon dispersion curves of CuAlS2 along several high-symmetry lines together with the corresponding phonon density of states are given. The thermodynamic properties were derived from phonon frequencies calculated within the quasi-harmonic approximation. The temperature dependence of various quantities such as the free energy F, entropy S, the volume thermal expansion alpha(V), the heat capacity at constant volume C-V, and the heat capacity at constant pressure C-P are computed. Our results are in good agreement with available experimental data and other calculations.