First-principles calculation of the dynamical and thermodynamic properties of CuInSe₂

摘要

We have performed detailed studies of the lattice d ynamics and thermodynamic properties of CuInSe 2 within the density functional perturbation theory and pseudopotential methods. The phonon frequencies at the . point of the Brillouin zone are calculated and their symmetry assignments are given. The calculated Raman and infrared active phonon frequencies are in excellent agreement with the experimental values and other calculations. The results for the phonon d ispersion curves of CuInSe 2 along several high-symmetry lines together with the corresponding phonon density of states are displayed. The thermod ynamic properties including the phono n contribution to the Helmholtz free energy ΔF, the phonon contribution to the internal energy ΔE, the entropy S, and the constant-volume specific heat C V are determined within the harmonic approximation based on the calculated phonon dispersion relations.