Lattice dynamical and thermodynamic properties study of ceria using density functional theory and Hubbard correction

Abstract

In this study, the lattice dynamical and thermodynamic properties of CeO2 were investigated with first principles density functional theories LDA, PBE and DFT + U approximations. The phonon dispersion relation, phonon density of states, Brillion Zone-center phonon frequencies, Born effective charge and polarizability of CeO2 were calculated to investigate the lattice dynamical properties. The value of acoustic phonon frequency TA (Γ) , TO1(Γ) and TO2(Γ) calculated with DFT + U approximation is in better agreement with experimental value as compared to LDA and PBE calculations. The polarizability of CeO2 decreases with increasing frequency and approaches zero with further increase in frequency. Moreover, the temperature dependence of Helmholtz free energy, internal energy, entropy, chemical potential and specific heat capacity at constant volume were analyzed to investigate the thermodynamic properties of CeO2. The lattice dynamical and thermodynamic properties of CeO2 calculated with density functional theories are in agreement with both experimental values and theoretical findings.