First-principles study on the electronic, optical and thermodynamic properties of ABO3 (A = La,Sr, B = Fe,Co) perovskites

Abstract

The electronic, optical and thermodynamic properties of ABO₃ (A = La,Sr, B = Fe,Co) perovskites are investigated using first-principles calculations. The obtained results indicate that SrCoO₃ and SrFeO₃ are metals, while LaCoO₃ and LaFeO₃ are insulators and all of them exhibit strong hybridization of the Fe/Co-3d and O-2p orbitals. By correlating the energy band structures with the peaks of the imaginary part of the dielectric function, we obtained the origin of each electron excitation to provide information about the active bands for the corresponding optical transitions observed in the experiment. Moreover, the Debye temperatures θ_D obtained from the phonon frequencies are comparable to the available data. Finally, the thermodynamic properties of the Helmholtz free energy F, entropy S, and constant-volume heat capacity C_v are investigated based on the phonon spectra.