Structural and Thermodynamic Properties oF Cu₂ZnSnS₄ Material: Theoretical Prediction

The present work aims to investigate the structural and thermodynamic properties of homogenous tetragonal Cu₂ZnSnS₄ (CZTS) absorber material in Kesterite phase using first-principle calculations based on density functional theory (DFT). This approach requires only knowledge of the atomic species and crystal structure to predict several physical properties of materials. The Quantum Espresso code within the Ultra Soft pseudopotentials (USPP) and the local density approximation (LDA) were used in the calculations. Equilibrium unit cell volumes, bulk modulus, as well as the pressure derivative of the bulk modulus are predicted. In addition, several thermodynamic properties, especially: the Debye’s vibrational energy, the vibrational free energy, the vibrational entropy, and the constant volume heat capacity at different temperatures T of Cu₂ZnSnS₄ material are calculated and discussed. Our study shows that the vibrational energy, the entropy and the constant volume heat capacity increase with increasing temperature, while the vibrational free energy decreases monotonously with the increase of temperature.