A DFT analysis of perovskite BaTiO 3 ’s structural and thermal characteristics

Abstract

During this study, the structural and thermodynamic properties of BaTiO3 were investigated using the pseudopotential method within the framework of (DFT), employing the Generalized Gradient Approximation (GGA-PBE) for the description of exchange-correlation energy. The structural calculations revealed that the lattice parameter reached a=4.0391A ̊, while the bulk modulus was estimated to be B=160.087GPa. These results showed good agreement with previously published theoretical and experimental values, confirming the accuracy of the adopted computational methodology. Furthermore, the thermodynamic properties of the compound were studied, including the heat capacity at constant volume, entropy, internal energy, free energy, and thermal expansion coefficient as a function of temperature. The obtained results indicated that the heat capacity, entropy, and thermal expansion coefficient increase progressively with increasing temperature due to the activation of lattice vibrations within the crystal structure. In contrast, the free energy decreases with increasing temperature, whereas the internal energy continuously increases as a consequence of the rise in vibrational energy of the atoms. The obtained results confirm the effectiveness of Density Functional Theory and the pseudopotential method in describing the structural and thermodynamic properties of perovskite materials. The good agreement achieved with previously reported theoretical and experimental results demonstrates the reliability and accuracy of the computational approach adopted in the study of this type of material.